[E]"Killing bottles," containing cyanide of potassium under a layer of gypsum, may be bought at most natural-history apparatus dealers, and are useful as relaxing dépôts.
[E]"Killing bottles," containing cyanide of potassium under a layer of gypsum, may be bought at most natural-history apparatus dealers, and are useful as relaxing dépôts.
Good things should always, when practicable, be set out at once, as the pubescence is apt to get matted if they are consigned for too long a period to the laurel or cyanide bottle; but such as remain unmounted can be put in a little muslin bag, and deposited in laurel until a more convenient opportunity. Beetles also, when taken in large numbers during an expedition into a productive locality, may be collected indiscriminately into a bottle containing sawdust (sifted to get rid both of large pieces and actual dust), slightly alcoholized, or with a small quantity of carbolic acid or cyanide of potassium in it. Each night, on reaching home, these will be found to be dead, and they can then be transferred to a larger bottle or air-tight tin can, partially filled with thesame materials and a little carbolic acid to check undue moisture. Filled up with sawdust, this will travel in safety for any distance, and almost any time.
Species of moderate size, say up to that of an ordinaryHarpalus, are in this country usually mounted on card. Much is to be said both for and against this practice: it enables the proportions and formation of limbs to be well appreciated, and it preserves the specimens securely; but there can be no doubt that it prevents an inspection of the under side, except at the slight trouble of extra manipulation in floating off in cold water and reversing, and that the gum used clogs the smaller portions of the insect that come in contact with it. Specimens larger than those mentioned should be pinned through the centre of the upper third of the right wing-case (never through the scutellum or thorax), and the limbs extended in position with pins on a setting board, made of a flat strip of cork glued on deal. Both these and the mounted examples must be left to dry, for a week at least, in the open air: if the boards are fitted in a frame, they can be reversed (as soon as the gum is dry in mounted specimens), so that the specimens are bottom upwards—dust cannot then collect on them, and there is less chance of mites attacking them. Specimensdry more rapidly in spring and summer than at any other time, and of course more readily in dry weather.
For mounting specimens, five or six small pieces of the finest and most transparent gum tragacanth, or "gum dragon," with rather less than the same number of pieces of clear gum arabic, are to be put in a wide-mouthed bottle with about a large wine-glassful of cold water. In a short time (twenty-four hours at most) the gum absorbs the fluid and swells; then add half as much more water, and stir the mixture, which, on being left for another twenty-four hours at most, will be ready for use. The mixture should be dull white, of even texture, and not quite fluid. Never make a large quantity at one time, or be persuaded to putanythingelse into it. Card for mounting should be the whitest, smoothest, and best that can be procured. "Four-sheet Bristol board" for large specimens, and three-sheet for ordinary use, are about the proper degrees of thickness. Robersons, of Long Acre, artists' colourmen, have promised the writer to turn out cardboard of this kind with an extra milling, to ensure a good surface. Upon strips of this card, pinned on a setting board, the insects to be set out are mounted, one at a time, and not too close to each other, each on a separate "dab" of the gum, the limbs being duly set out with a fine pin or needle mounted in a paint-brush stick. A pin withthe point very finely turned, so as to form a minute hook, is very useful; and for extremely minute work a "bead-needle" is valuable. The gum-brush should not be used in setting, but one or two very fine-pointed camel's-hair brushes may be found of advantage. Before mounting, reverse the specimen on the blotting-paper, and brush out its limbs as far as practicable with a damp flat brush. Very refractory individuals may require to be gummed on their backs; as soon as the gum is dry, their limbs can be more easily got into position, and they can then be gently damped off their temporary mount, and treated as above.
A small pair of brass microscope-forceps, ground or cut to a minute point, will often materially assist in getting refractory limbs into position. French white liquid glue (not made of shell-lac) is useful for fastening down larger specimens, as it is very strong and dries readily; and with a very small quantity of it rows of specimens can quickly and securely be roughly mounted, in the Continental way, which is preferable in many cases to leaving the insects for a long time in laurel before setting them out. Such specimens can afterwards, if desired, be relaxed by leaving them on damp sand, or in the cyanide or laurel bottle, and be then set in the way above indicated.
Care must be taken, in setting, not to put the specimen lop-sided on the card, or to distort its segments unnaturally by pulling them out of position, &c., and not to allow gum to lodge anywhere on the upper surface. It is easy, soon after a specimen is securely mounted, to remove with clean water and brush any superfluous gum. In preparing such insects as are liable to "run up" in drying (e.g. theStaphylinidæ), the abdomen should be duly pulled out by a bead-needle inserted at its apex; and to prevent the contraction of the internal muscles in drying, this part may be held with the liquid glue above mentioned. Usually, by putting these insects as soon as mounted into a box and keeping it closed for a few hours, while the first drying takes place, the proper dimensions of the abdomen may be preserved, and thus the natural facies of the insect retained. The contents of the bodies of very large insects may well be removed, either by the anal orifice, or by an incision on the lower side of the abdomen. The Oil-beetles (Meloë) alone require careful stuffing. This is best done by separating the entire abdomen from the metathorax, beneath the elytra, and close to their point of insertion: the body is then easily emptied and washed out, and may be filled with cut-up wool, which packs closely; when gummed on again, the junction is not visible,and the entire insect preserves its wonderfully obese appearance.
To save time, in mounting many specimens, it is better to merely gum straight on the strip of card as many specimens as can be managed at a sitting. The left side of each of these can then be slightly damped with clear cold water, and its left limbs set out: when all are thus done, the first one will be nearly, if not quite, ready to have its right side treated in like manner; and so on to the end. Very refractory specimens will sometimes require to be even held down with little braces of card on pins, and to have each limb damped and set out by a separate operation. The card of large specimens will often curl upwards in drying, owing to the amount of damp: to counteract this, the lower face of the card may be washed with a wet brush, just before gumming its surface.
Before putting insects away, when dry, the individual specimens should be cut off the strips of card by a straight cut on each side, one at right angles to the sides in front, and another behind, all (except the last) close to the tips of the limbs as set out, so that the whole card forms a parallelogram. A very little practice will enable the operator to do this both certainly and quickly. No two individuals (save perhaps a male and female, of whose sexualrelations there can be no doubt, or an example mounted on its back, to show its under side, along with a member of the same species) should be allowed to continue on one card; much less should a row be left together. The reason of this is, that in many cases species closely resembling each other often get confused; and it is, moreover, difficult to get a glass of anything but a very low power to bear upon all parts of the individuals without injuring some of them. Each specimen should have sufficient card leftbehindit to allow of a glass of high power being passed between it everywhere and its pin. The pin should perforate the card in the middle of, and close to, its hinder margin; and the whole card be lifted three-fourths up the pin, to keep it from mites and dirt as much as possible. Proper entomological pins can be obtained of all sizes at the agents of Edelsten, 17, Silver Street, St. Martin's-le-Grand; also (with all other apparatus) of any natural-history agent or dealer in London; such as Mr. E. W. Janson, 28, Museum Street, or Cooke, New Oxford Street. "No. 8" pin is, perhaps, the most useful size. In removing many specimens, proper insect forceps will be found handy: these can be obtained at the two last addresses; or of Buck, cutler, Tottenham Court Road.
Specimens will occasionally become discoloured with grease, usually from defective drying, thoughmany water beetles and internal feeders, and most autumn-caught specimens, are specially liable to this defect. Benzine is an effectual remedy for it and for mites, and can be liberally applied with a brush. Carbolic or phænic acid, dissolved in that fluid (or alone, see p. 64), is an effectual safeguard against mould from damp; and when in solution with water, this acid has been found useful as a wash for card and boxes, which then are not attacked by mites. To re-card a specimen that has become discoloured (whether from either of these causes, or from age), it is only necessary that it should be floated in cold water for a few minutes; the insect can then be dried, well saturated with benzine, and again mounted, looking as fresh as ever. But, in re-carding specimens, it is necessary to be very careful with such as were originally kept too long in a laurel or cyanide bottle, as they are apt to become so rotten that a little damp will cause a "solution of continuity."
As to storing the specimens when quite dry, I can add nothing to the excellent observations of Dr. Knaggs, at p. 65; the same remarks applying with equal force toColeoptera; except, perhaps, that, even when the collector has (and is satisfied with) a cabinet, he is likely, in proportion to therealwork done by him, to establish type-boxes of all the difficult groups.
For the examination of insects, readily manipulated by being pinned singly on a square, flat, thick piece of cork or bung, a pocket glass is, of course, necessary. In this case, the best instrument is the cheapest in the long run, whatever its cost; and one by a good maker, such as Ross, with modifications of four powers, will suffice for any ordinary work. For very small species, a Coddington, of the clearest definition and highest power attainable, is of immense help. But when the collector finds that he needs a compound microscope to separate species, it is the firm opinion of the present writer that that collector had better take to some other pursuit than studyingColeoptera. To anyone, however, whose researches entail an examination of the minute cibarian and other organs of beetles, whether for purposes of classification or otherwise, the compound is absolutely necessary; though even then the lower powers are usually sufficient. For rough dissection, all that is needed are an oculist's very small lance-headed dissecting-knife and a stout and fine needle. With these, under a lens mounted on a little stage to allow the free use of both hands, much may be done. The writer, however, has seen and used a very pretty (and comparatively inexpensive) dissecting-stand, with various powers and much latitude of motion, by Ross.
After mentioning that, in sending mounted beetles by post to correspondents, it is far more practical to use astrongbox, not too deep, to fasten the pins securely, with a layer of manufactured wool in the lid (glazed side towards the beetles, so as not to catch limbs), and to put more wool outside, and write the address and affix the stamp on a label attached, than it is to pack carelessly, write "With care" outside,[F]and then grumble at the post-office because the insects are broken,—I think I cannot, with use, say anything more upon beetles in their preserved condition; and I will therefore now give some hints as to their haunts when alive.
[F]It is, however, always as well to write "Insects," signifying contents that are "caviare to the million," and therefore not likely to be appropriated en route.
[F]It is, however, always as well to write "Insects," signifying contents that are "caviare to the million," and therefore not likely to be appropriated en route.
To exhaust the accidental-capture system above alluded to, mention must first be made of sand-pit collecting, a most profitable employment, especially in spring and early summer. A clean, straight-sided silver-sand pit is the best, and if in or near a wood its attractions will be at their highest. Beetles, flying of an evening and by night, dash against the pit sides and fall to the bottom; others merely crawl in for shelter, or tumble over the sides, and many seem attracted by the mere damp at the bottom or in the corners. Old collectors used to recommend asheet spread out to attract insects; and there is no doubt that a certain number can be found by such means, just as they can be picked up floating on horse-troughs or on ponds. Artificial traps exist in the corridors of the Crystal Palace, some half-inclosed country railway stations, and such places; crawling up the windows of which many specimens are to be found. But these can only be considered as indications of what species occur in the district, as they are mere stragglers. Deliberately laying traps in sand pits, on commons, &c., will be found most productive. Small dead animals, fir branches, dead leaves, &c., can be examined time after time with profit in such situations. Burying a stout branch with the bark on, leaving the top above the soil, and periodically examining it when damp and nearly rotten, has been found effective; many insects collecting beneath the loose wet bark.
After heavy floods, as during severe droughts, beetles may be found in great profusion; in the former case, by sifting the refuse left by the water; in the latter, by diligently examining the damp residuum of former ponds, and if no damp be found, by even searching below the surface where it last occurred.
The wet hay, often decayed and mouldy, at the bottoms of stacks, which bad farmers have placeddirectly on the ground, will be found to teem with beetle-life; as will the margins of dung and vegetable-refuse heaps, wood-stacks, cut grass, &c.; and many good things may be taken by gently waving a light gauze net to and fro, just before sunset, close to such places, whither the instinct of nature impels the flight of myriads.
In winter, isolated tufts of grass in wet places, on the margins of streams, the crests of banks, &c., must be cut close to the ground, and gently torn in pieces over brown paper. Wherever many insects seem to be found, it will in most of these cases be found advisable to sift the fragments, and bring home the beetles and small stuff unexamined in a bag with a string at the neck to prevent their escape. Moss should be treated in this way, and the layers of black and rotting leaves found in woods, especially at their outskirts. Beech leaves usually produce many species, and the autumn and spring are the best times for hunting for them.
In winter, also, many species will be found hybernating in grass at the roots of trees, under bark, &c., in conditions not usual with them at other times.
In autumn, fungi, in woods especially, will be found most productive.
General sweeping, except during the winter, willalways be more or less remunerative. No general rules can be laid down for this; in a good neighbourhood (on chalk or sand, or, better still, in a district where both these soils are found) beetles will swarm almost anywhere in due season, and the most unlikely-looking spots will frequently be found the best in the end. In luxuriant herbage, among low shrubs, in the close-growing vegetation of hill-sides, the sweeping net may be plied with success; but the best way, with allPhytophagaat least, is to start with a fixed idea as to catching certain definite species, and then, at the right time, to hunt for such plants as these are known or supposed to frequent; and, such failing in the district, to try their allies. Of course, the collector will not fail to sweep flowers in woods and lanes, whereon, in the hot sunshine, many showy beetles bask. Many good things will be found by sweeping under fir trees, especially towards evening, and even by night; in many places, especially marshes, nocturnal feeders may be secured by the vague use of this net. By night, also, many species may be found at sugar put on trees for moths, and on ivy or sallow-blossom.
Beating is most productive in early summer, especially in the second year's growth of young cuttings in woods; and the oak, hazel, and poplar will generally yield many species to the tap of thestick. Good thick, and especiallyoldhedges, must also be always carefully thrashed into the net; very many good things, otherwise not procurable, will reward this toil. Another scheme for getting rare species is to beat the tops of trees with a long pole, placing beneath a sheet or tent covering.
Breaking away the extreme edges of banks, throwing water on them, treading heavily on the margins, diligently examining grass and roots close to the water, reeds (especially if cut and on the ground in heaps), &c., will bring to light great numbers of wet-loving beetles. Water beetles, pure and simple, must be dragged and dredged for, especially round water plants beneath the surface, and along the sides of ponds, in eddies of running streams, in the moss on stones in them, and on the stones themselves, &c.
TheCoprophagawill be found readily in the droppings of variousMammalia, and also in holes bored in the ground beneath, often to a great depth. An easy and clean way to secure them is to throw droppings, ground and all, into water, the beetles coming to the surface.
As to wood beetles, they must be sought for under and in bark, in solid wood, in decaying branches, and such places; a rule to be remembered is, that most of these occur at thetopsoftrees: hence the paucity of so many species in collections. Indeed, to properly hunt for the majority of them, it is necessary to obtaincarte blancheand a ladder, if any success be hoped for. Felled trunks are, of course, easy to manipulate; and their freshly-cut stumps, exuding either resin or a peculiar and often sweetmucor, are very attractive to many beetles, as is freshly-cut sawdust, and most especially the (to us) fetid and acrid juice resulting from the attacks of the larva of the Goat-moth. Rotten fruit, &c., are also not to be passed by without examination. Many small species occur in, or can be obtained from, the topmost twigs of trees blown down by the wind.
Dead animals, as before mentioned, must be examined, as must the vegetation and soil near them. A keeper's tree in a wood will always produce something for the collector, who need only hold his net beneath the gibbetedferæand bang their hides and bones with his beating-stick. During different stages of decomposition and desiccation, beetles of widely varied affinities will result from this method of collecting.
Ants' nests would require a special notice, so productive are they: their material can be sifted and their neighbouring "runs" or paths examined, traps laid near or on them, and periodically clearedout, &c. Bees' and wasps' nests also produce good, though fewer species, and are, moreover, not quite so easy of access. The nests of birds, especially if the latter are gregarious, and, indeed, the habitations of any animals, will be found to harbour many beetles, amongst other insects.
In gardens, the beetle collector should lay cunning traps of cut grass, twigs, planks, bones, &c.; by a periodical examination of which he will secure many good things. If there be a hothouse about the premises, it and its belongings will always act as a bait.
Large tracts of waste land and commons, though superficially apparently unproductive, often contain congregations of good species, in some little oasis of damp or vegetation; moreover, on them several peculiar beetles occur. Hills and mountains will often suddenly repay the toil of the collector, who has despondently worked his way up, turning over stones, and finding comparatively nothing. The moss, &c., attending the channels of any streams in such places should be carefully searched, and the stones on the top especially not neglected. River banks and salt marshes are invariably frequented by good insects, and the very heaps of seaweed, dry or wet, on the shore harbour countless beetles. In such places small sand-loving plants should bepulled up by the roots, and, with the neighbouring soil, shaken over brown paper. The sand itself may in many instances be scraped, and burrowing beetles brought to light; but if the hunter comes upon a dead fish or bird, a full bottle will be his.
Thus it will be seen that almost every locality contains beetles, if the collector can only detect them (and it may be as well here to impress on him that it is better to bottle a dubious insect and examine it at home, than to reject it for beingapparentlycommon). Still there can be no doubt that certain soils and districts are much more productive than others; for instance, most of the midland and western counties, and some of the south-western, are not by any means so prolific as the eastern, southern, and many parts of the northern districts of Great Britain; clay being the worst of all soils for the Coleopterist.
The collector will do well, after a first hurried "burst" at all beetles that come in his way, to select a special group, and lay himself out to work it carefully, buying or borrowing the works of authorities upon it, and making himself master of thebotanyconnected with it, if it be a group of plant-frequenting habits. By such a way of working, he will more quickly, though step by step, acquire a good collection, and a stock of useful knowledge,than by any other. He will of course keep a register of the date and place of capture, and any peculiarity of habit of each insect he takes. Figures of the date of the year (usually the last two are sufficient), followed by another set, commencing with 1, will generally be quite enough; corresponding entries being made in the first column of a ruled diary. These figures may be written in ink on the under side of the card of a mounted specimen, or on a circular disc of paper, pierced by the pin of one too large to be carded.
VI.
HYMENOPTERA.
By John B. Bridgman.
Having been asked to give some instructions as to the method of setting and preserving the aculeateHymenoptera, it is with great pleasure I comply, and I hope it may be the means of inducing others to collect these insects. To begin at the beginning, it is almost needless to state that the females of all of them (a few of the ants excepted) are furnished with stings, but with very little care one need never be stung. As Mrs. Glass says, "First catch your hare": so first I shall give a few instructions where to look for and how to catch these insects. All the apparatus necessary is a gauze ring-net, a cyanide bottle, and a pocket full of small card pill-boxes; the cyanide bottle is best made by wrapping a small piece of cyanide of potassium in two or three thicknesses of blotting-paper, tying it round with cotton to prevent it shaking out, then fixing it to the bottom of a wide-mouthed flat bottle with sealing-wax, which is made to adhere firmly to the glass by heating the glass carefully over a lamp, and thencorking it up. The pill-boxes ought to have the tops and bottoms fastened in with liquid glue (a preparation of shell-lac). These are all that are required to catch and bring home the game; which is to be looked for at the flowers of trees, bushes, and plants—one season's experience will teach the best, as some species frequent one, some another, and some almost all. The flowers I have found the greatest favourites are sallows, willows, sycamore, holly, blackthorn, bramble, hawkweeds, ragwort, thistles, and umbelliferæ. Some bore in putrescent wood, and must be looked for on or in the neighbourhood of old posts and palings; some are to be found flying about dry banks, hard-trodden pathways, on heaths, while old sand pits are favourite places; but they should be sought for in any warm, rough, weedy spot; and some may be obtained by digging them out of their burrows with a trowel. My plan of proceeding, after having got one in the net, is to catch hold of the net so that the insect is inclosed in a sort of sack, I then uncork the cyanide, and introduce that into the sack, holding the net firmly round the neck of the bottle, so that there is no other escape for the insect from the net but into the bottle, then gradually work the insect into the bottle and close the mouth with several folds of the net, watch my opportunity and insert the cork:when the insect is stupefied, which happens in a few seconds if the bottle is slightly warm, I turn it into the pill-box. A word of caution: it is necessary to be methodical in carrying the boxes. I always keep the empty ones in my right-hand pocket, and the filled ones in the left-hand one, as, if they are carried sometimes one way, sometimes another, sooner or later a previously filled one will be opened to put an insect in, which will result in the former tenant speedily making room for the new comer; and my experience has been, if you do lose anything it is generally your best capture.
Having got home with the left-hand pocket more or less filled, turn the boxes out, preparatory to killing the contents, which must be done with burnt sulphur. My mode of proceeding is as follows:—I stupefy the contents of each box with chloroform, in a manner I will describe farther on. Having stupefied them, I empty them all into a short, wide-mouthed, round bottle, having a piece of glass tube put through the cork; the mouth of the tube is plugged with cotton wool, not too tight, to act as a strainer. I then put this in a Nabob pickle-bottle (any other bottle will do as well), through the stopper of which I have drilled a hole about a sixteenth of an inch in diameter, in which is fixed a copper wire, having a shallow tin cup at the end.In this tin cup is placed the sulphur. The tin cup is then held over the flame of a lamp, gas, or candle, till the sulphur is burning, then put it into the bottle and press it down. When all the oxygen is consumed the sulphur goes out. Leave them for about three hours, take them out, and put them into a damp box for twelve or more hours: they will then be in a splendid condition for setting. To stupefy the insects I tip the lids on one side, put them into the sulphur bottle, pour a drop or two into the tin cup, and put it into the bottle. Be careful not to chloroform them too much, as if killed so they become so rigid that it is with difficulty they can be set.
Having killed them, there only remains to pin and set them. There are various sizes of pins used; most collectors have fancies of their own on this subject; I shall therefore only say what is my practice. The pins I use are D. F. Tayler & Co.'s, New Hall Works, Birmingham; No. 15 for bumble-bees only; the other sizes I find most useful are 15, 10, and 18. Some pin the insects straight, and some with the pin inclining forward. Having pinned them, the next thing is to set them. There are two ways of doing this; one is, cut an oblong square of stout cardboard, and put a pin through one end; after the legs are stretched out, this is put into thecork, one on each side, till the upper surface of cork is just below the level of the wings, which are then laid out on the card, and held there by a brace the same shape as the table (seeFig. 28). If the insect has been properly killed, the legs and antennæ will keep set out without the aid of pins; if not, this is done with bent or straight pins, as may be necessary. The other way is a "hymn of my own composing."
Fig. 28 Insect set with Table Braces.
Fig. 28 Insect set with Table Braces.
Fig. 29 Wood, with the Strips glued on.
Fig. 29 Wood, with the Strips glued on.
First take one of the strips of cork as sold at the shops, paper it on both sides with thin soft paper; then take a piece of wood a little larger than the cork, about half an inch thick; on this I glue strips of cardboard, or thin wood, according to the size of the insect, side by side, and as far apart as necessary (seeFig. 29). These being dry, I glue the sheet ofcork on to the top of the strips, which leaves it looking like a succession of bridges. When this is dry the cork must be cut through between the pieces first fastened on the wood. These pieces are then taken out and glued to the wood (seeFig. 30); this leaves many setting boards, something similar to the single rounded ones used by Lepidopterists; but these are flat—they want to be just deep enough for the insect and wide enough to allow the legs to be stretched out. A little practice will soon determine the size. The wing I hold down with small triangular braces. Each board will hold about seventy or eighty insects; beneath I put the date they were set, and leave them on the board about a month to dry, as if taken off too soon the wings spring. Always put a label to each specimen, either with the date or a number corresponding to one in a book, in which enter the date and locality.
Fig. 30. Ditto, side view. A, the same with the cork glued on; B, cork; C, the same with the cork cut through at the dotted lines in A, and fastened down.
Fig. 30. Ditto, side view. A, the same with the cork glued on; B, cork; C, the same with the cork cut through at the dotted lines in A, and fastened down.
One more observation and I have done. Sometimes one comes across an insect whose rigid wingsseem to defy all attempts to set; in such cases just press firmly at the back part of the thorax, between that and the abdomen, towards the pin, and the wings will sometimes fly open of their own accord, or will allow of their being easily set in the required direction, which should always be set well forward.
VII.
LAND AND FRESHWATER SHELLS, ETC.
By Professor Ralph Tate, F.G.S., etc.
A young friend, desirous of entering upon one of the most accessible natural history pursuits, that of the study of Land and Freshwater Molluscs, begged of me some practical hints on the collection and preservation of these objects of our woodlands, waysides, and watercourses. Believing that this kind of work offers a good stepping-stone to the study of nature in its more extended forms and complicated relations, I was most anxious to help my tyro naturalist, and that beyond his utmost expectations, as I made a few initiatory trips with him in a search for the coveted treasures.
Our equipment was simple and inexpensive, consisting of a block-tin saucepan finely perforated at the bottom, about six inches across, and having a hollow handle of a size to receive firmly the end of a common walking-stick—such adredgeor asifterwill cost ninepence or a shilling at a tinman's; secondly, of a pocket lens; and lastly, of a variety of boxes, and a bag to contain specimens of different sizes. Thus provided, our first excursion had for its objectan examination of certain neighbouring ponds and streams. My pupil, guessing the use of the perforated saucepan, makes his way to the nearest pond, fixes the improvised handle, dashes in thesifterwith impatient ardour, and having brought up a quantity of mud from the bottom, looked upon the oozy mass with despair. Patience, my lad! Remember that the pleasure of success in science is the higher the greater the labour expended in obtaining the objects of our search. Expect failure now and again, but do not be disheartened.Ohne Hast ohne Rast, should be the motto of every naturalist. Now, shake the tin in the water, keeping its rim just out of the water, dipping it down now and then. That is well; thus you see that you have cleared off the mud, and what you want is probably left behind along with the rubbish. What, nothing! Come, try again; but this time scrape the sifter along the surface of the mud, and I am confident that you will find something to reward you, and with much less trouble and display of temper. In this way, after repeated trials, a number of shells were secured and transferred to the boxes. Then, after the first gush of excitement is over, we retire to an adjoining bank to con over the spoils, and I to make mention of the various habits of freshwater snails, and consequently of the different modes of search. My young friend's enthusiasm isaroused by the mention that a few large mussel-like shells are inhabitants of our fresh waters, and great is his haste to be up and again doing, in the hope of adding some of them to his stock. But in vain were his many attempts to find them in the pond which had already yielded us such a variety. "Do they live here?" is at last the anxious question. "No; but let us away to yon sluggish brook, for it is in such that we may expect to meet with them." "Now I see them. Are not those their ends just peeping above the mud?" And full of eagerness he dashes in the dredge, but with little result, excepting that of a dead shell or two. "Oh! how can I get them? Shall I take off my shoes and socks and wade for them?" "Well, you might secure them that way, and sometimes it is the only way, but on this occasion I do not think it necessary. Come, we will move a little higher up, where the stream is clear, and the shellfish undisturbed. Observe the gaping ends of the shell, and thus I push the end of the stout rod between the partially-open valves; now they close upon the stick, and so we bring our prize holding on to the stick to the bank."
"You will recollect," addressing my companion, "that in the muddy pond we have just left, we chiefly got small bivalves and only a few snail shells. I have already told you that water shells differ muchin their habits, and that consequently our search for any particular species, or set of species, can only be successfully carried on when that knowledge is our guide. Those little bivalves, and a few of the snails that we have gathered, habitually live at the bottom, and will of course be brought up in the dredge when that implement is dragged over it; but there are many shells which live at or near the surface, and which feed on the submerged and floating plants. Therefore we must seek out a weedy pool if we would increase the variety of our collection." Such a spot is reached; and the dredge is brought into requisition, anon to snatch up a floating snail, or again to sweep over and through the plants, varying our occupation by dragging to the margin the tangled masses of weeds; by all of which means a considerable number of the class of air-breathing water snails was obtained—admonishing my young friend that this last plan does very well when the plants grow in dense masses, because when thus interlaced they form a natural net to catch those snails which on the slightest disturbance lose their hold upon the weeds, and which would otherwise fall to the bottom.
Yet another plan remains to be pursued, one by which the few small shells hiding among the roots of the plants may be secured. Obviously the dredgemisses such; but by pulling up the plants by their roots, and well shaking them in the half-sunken sifter, we yet after all obtain them.
From causes which need not be explained here, the shells living in some ponds are all much eroded, or coated with a ferruginous deposit; it will be desirable therefore to find out the localities where specimens are in the best condition, so that you may have typical specimens for comparison before an extensive collection is made.
Our experience is, that though a considerable number of species may be obtained from a ditch or pond, yet a few are found as the sole molluscan tenants of particular sheets of water; that lakes exhibit a dearth of life, and that the greatest variety is often to be met with in canals; but should a search be carried on in them, avoid the towpath side, for reasons that a little thought will readily suggest.
Living near the sea, and within a short distance of wooded hill-sides, we had within a limited area such a variety of physical features that we were led to infer the existence of a rich molluscan fauna for the neighbourhood. Our second excursion was devoted to a search for snails along the sea margin and shores of the estuary. Proceeding along the low sand-dunes—at first sight a most uninterestingspot—Helix caperata,H. virgata,Bulimus acutus, and a few other snails, were found clustering upon the low stunted vegetation in such numbers, that handfuls might have been gathered within an area of a few square feet. Leaving the seashore, our way led us over the foreshore of the mouth of the river, crushing under our feet at every step shells ofCardium edule,Scrobicularia piperata, and a few other bivalves which find a congenial habitat in such situations. Gaining the muddy margins of the higher part of the estuary,Conovuluswas looked for, and found under the stones along the high-water mark. Higher up the river the rejectamentum on its banks was carefully turned over, and we were successful in securing a number of land shells. The animals, of course, do not live in such places; but their empty shells, which alone were found, had been brought down from the land surface by the agency of the streams and tributaries of the river. Nevertheless such anomnium gatherumshould demand attention, as its contents give an insight into the character of the land and freshwater forms within the area of drainage of the river.
The number of estuarine species which have a place in our works devoted to British land and freshwater snails is very few, and the majority, moreover, are confined to the margins of the tidalrivers in the south of England. ThusAssiminea Grayana,Hydrobia ventrosa, andH. similis, live on the mud banks beneath the shade of sedges and rushes, skirting the Thames below Greenwich. To gather these small shells singly is a tedious operation; but if a thin piece of flat wood, or other substitute as the ingenuity of the collector suggests, be used to scrape lightly over the surface of mud, transferring the mass to thedredger, and washing in water, a number of specimens sufficient to stock every private cabinet in the country may be obtained in a short space of time.
For the third initiatory excursion our steps were directed inland, and as we proceeded the hedgerows, mossy banks, and margins of watercourses were diligently searched, finding aHelixhere, aPupaor aSuccineathere. Gaining the woods, we turn over the damp leaves, grub under the clumps of ferns and wood-rushes for small Helices, Pupæ, and the like; scan the trunks of the trees for the climbingClausiliæ,Bulimi, andHelices, not unmindful that each little dirt-like mass is probably aBulimus obscurus, which, by covering its shell with mud, thus exhibits a protective faculty, and often escapes detection. Raise the rotting bark forBalia; lift the stones at our feet, or roll away a log forHelicella,and other small shells which usually live in such situations.
From all this we learn that each species affects certain stations, and therefore, with the knowledge of the circumstances in which they are found, we may set out with some definite idea as to what we are likely to meet with; and, in consequence, when to collect and where to collect are regulated by the unvarying habits of the objects of our search.
Now, a large portion of the life of most land snails is passed in a state of sleep. Those living in open situations are inactive during the heat of a summer's day, and when there is continued drought; but on the first shower, or after the fall of dew at night, they recover and move about in search of food. Cold acts much in the same way as heat, and with the fall of the leaf they retire to winter quarters in crannies of rocks, crevices of walls, under heaps of decaying vegetation, &c., or bury themselves in the soil, there to hybernate till the genial showers of spring awaken them.
The best time of the year for collecting is in the autumn, when the shells are full-grown. Those collected in spring have lost much of their original beauty by exposure to the rains and cold of the winter months.
As regards the particular time of day to collect with advantage, it has already been implied that a search in an open country should be prosecuted after a shower of rain, or during early morn. In damp woods, where throughout the day the air is sufficiently moist to maintain the animals in full activity, no such considerations determine the best time for collecting. In such places, light is usually the desideratum, and consequently I have found that a search conducted at midday in a clear sky has been amply rewarded.
Land snails exhibit a partiality for calcareous soils, not only by those living on downs and hill-sides, but also by the woodland species.
Having spent the forenoons of three days in gathering slugs and snails as before detailed, one evening was devoted to the preparation of the specimens for the cabinet.
The first step was to remove the animals, and, as all know, it is neither an easy nor a clean task to separate the living snail and its house; but kill your snail, and the muscular connection with the shell being severed, its whole body is readily taken out by means of a pin—why, it is just like picking periwinkles; and if the proclivities of our childhood's days are not entirely obliterated, cleaning out larger snails from their shells will be a task requiringno teaching. But, with regard to the smaller kind, it is another matter, and it will be my duty to show you how to set about the work.
Now pick out those shells, the apertures of which are wide enough, as it seems to you, to permit the removal of the dead body of the snail by a pin. You may also place with them the larger bivalves. All these we will boil to kill the animals; then strain off the water, and wash with cold water. By this means the bodies contract, and being firmer are not so liable to be broken in the process of removal. Shake the water out of the empty shell, and place them before the fire to dry; do not rub them, but particles of dirt may be gently flicked off by the aid of a camel-hair brush. Thus we treat the larger snails. Now for the mussels. Doubtless most of the dead bodies will have fallen out between the open valves while in the water; should any remain, a slight shaking of the shell held by the hand in the water will remove the contained body. Taken from the water, the valves gape widely; dry the inside and outside with a cloth, and having tape or cotton at hand, close the valves by the pressure of the thumb and fingers of the one hand, and with the end of the thread between your teeth, wind the thread two or three times around the shell with the other; now tie the thread as tight as you can. "Yes,I have done so, but still the valves are not closed." True, this is because of the elasticity of thread. If, however, you will take the precaution to wet the thread before tying, you will find that the tie is more secure, and that there is less difficulty in making the second knot.
With patience and a little skill, bivalves as small asCyclas corneamay be treated in this way. But the smallerPisidiums, and some of the minute snails, asCarychium minimum, may be prepared for the cabinet by gently drying them in sand; too great a heat causes a transfusion of the carbonaceous matter of the animal into the substance of the shell, which is thereby discoloured.
There still remain for treatment such shells asClausilia,Bulimus,Helicella, some Helices, &c., the animals of which retreat, on the least irritation, beyond the reach of a pin, and whose shells, indeed, will hardly bear the rough handling almost necessary when a pin is used. Their bodies might be dried within the shells, but if it be possible to remove some portion only of the animal, an attempt should be made to do so.
Land snails, when placed in water, do their best to effect an escape from a medium so fatal to them; their efforts are usually exhibited by stretching out their bodies to the utmost, swaying them to and froas if in search of a foothold. Taking advantage of this propensity, the snails should be immersed in tepid water, because the majority, after a day or two's confinement in the collecting boxes, will be in a dormant condition, and warm water has a greater resuscitating effect than cold. When all the snails are struggling to find a way out of their unpleasant situation, gradually add hot water so as to kill or paralyze them while in an extended state. They may now be thrown into boiling water, the better to relax the muscular attachments, and the bodies, or so much as will come away, dragged out by forceps, or a pin passed through the foot. The shells may now be dried in sand, as before mentioned.
In cleaning the shells of some species, great care is needed, so as not to remove the hairs or bristles which clothe the surface of the epidermis.
The shells of such snails asPaludina,Cyclostoma, &c., &c., would be imperfectly illustrated without the opercula or lids which close the apertures of their shells. Each one should be detached from the foot of the snail, the interior of the shell plugged with cotton wool, and the specimen gummed down in its natural position.
The preservation of slugs requires separate treatment, and I can give but little additional information to that published in my 'British Land andFreshwater Molluscs' an extract from which is subjoined:—
"As regards the internal shell, it may be obtained by making a conical incision in the shield, taking care not to cut down upon the calcareous plate, which can then be removed without difficulty. The animals can only be conserved by keeping them in some preservative fluid; but the great object to keep in view is to have the slug naturally extended. Most fluids contract the slugs when they are immersed in them. The slugs should be killed whilst crawling, by plunging them into a solution of corrosive sublimate, or into benzine. Models in wax or dough are sometimes substituted for the animals. A writer in the 'Naturalist' gives a process for the preservation of slugs, which he states to answer admirably, and to be very superior to spirit, glycerine, creosote, and other solutions:—'Make a cold saturated solution ofcorrosive sublimate; put it into a deep wide-mouthed bottle; then take the slug you wish to preserve, and let it crawl upon a long slip of card. When the tentacles are fully extended, plunge it suddenly into the solution; in a few minutes it will die, with the tentacles fully extended in the most life-like manner; so much so indeed, if taken out of the fluid it would be difficult to say whether it be alive or dead. The slugs thus preparedshould not be mounted in spirit, as it is apt to contract and discolour them. A mixture of one and a half parts of water and one part of glycerine, I find to be the best mounting fluid. It preserves the colour beautifully, and its antiseptic qualities are unexceptionable. A good-sized test-tube answers better than a bottle for putting them up, as it admits of closer examination of the animal. The only drawback to this process is, that unless the solution is of sufficient strength, and unless the tentacles are extruded when the animal is immersed, it generally, but not invariably, fails. Some slugs appear to be more susceptible to the action of the fluid than others; and it generally answers better with full-grown than with young specimens. But if successful, the specimens are as satisfactory as could be desired; and even if unsuccessful, they are a great deal better than those preserved in spirit; for, although the tentacles may not be completely extruded, they are more or less so'".
The Testacellæ I have treated in the following manner: by partially drying them in sand, and removal of the soft parts through a cut in the length of the foot, filling up with cotton wool and a renewal of the drying.
Our land and freshwater snails have other structures besides their shells which should claim ourattention. These, which include their jaws, tongues, and some other minute parts, are not so inaccessible as one is at first too apt to consider, and are deservedly in favour as microscopic objects requiring a low power. I shall assume that the collector has preserved the bodies or the heads of the snails in spirit, which he has removed from their shells in the process of preparing them for his cabinet. He will take care to keep separate the animals of each species.
A last word upon the mode of displaying the shells in the cabinet. Here one has considerable choice, as they may be kept in open card trays, or in glass-topped boxes, or gummed on cards, papered boards, or glass tablets. Loose specimens admit of ready examination, whilst the method of mounting permits an arrangement of individuals according to size and locality, and is much to be preferred.
VIII.
FLOWERING PLANTS AND FERNS.
By James Britten, F.L.S.
PART I.
The kindred subjects of the collecting of plants and their arrangement in the herbarium have been treated of over and over again, and it might almost seem as though nothing further need be said upon the matter. But in spite of all that has been written, it cannot be said that anything like uniform excellence has been attained, either in the collecting or drying of specimens: on the contrary, much carelessness is still exhibited in both particulars, and the following remarks on the subject may therefore be useful to some, at any rate, among the readers of 'Science Gossip.' It has been found impossible to treat both points adequately in one paper, so, on the present occasion, we shall devote ourselves to collecting, leaving the arrangement and matters connected therewith for another occasion.