Encrusting Cyclostomata.
Colony erect. Branches of two or one series of zooecia, divided at intervals by chitinous joints. Ovicells pear-shaped.
Crisia(Fig. 237)
Colony more or less circular, discoidal or cup-shaped, sometimes forming secondary colonies by marginal budding
65
Zooecia separated by calcified interspaces, which may contain large pores, often difficult to distinguish from the orifices
66
No large pores as above. Orifices not spiny. Zooecia nearly always contiguous, except where an ovicell is developed
67
Colony composed of one or more convex discs, bearing radial ridges, each composed of many zooecia
Domopora
Colony encircled by a thin calcareous lamina, which gives rise to new zooecia, its centre usually devoid of zooecia when adult, and often bearing the orifice(s) of the ovicell. Zooecial orifices often spiny.
Lichenopora
Zooecia with a long, tubular, free portion, in some cases curved in a horizontal plane. Colony fan-shaped until a late stage.
Tubulipora flabellaris
Tubular portion absent, or for the most part curved in a vertical plane. Some of the orifices may be closed by a calcareous plate. Colony circular or bluntly lobed
Diastopora
Zooecia in one or few series, forming a linear or branched colony, which is closely adherent, but may give rise to short erect portions. Branches narrow, but often broadening at their ends. Zooecia usually with a free upper end
Stomatopora
Colony broadly lobed, some of the zooecia in transverse or oblique ridges composed of contiguous zooecia, arranged like a row of organ-pipes
Idmonea serpens
Colony broadly lobed, or fan-shaped; zooecia in many series, which are not arranged like organ-pipes
Tubulipora
Well branched. Orifices confined to one surface of the colony
70
Zooecia in transverse rows, their upper ends united in the manner of a row of organ-pipes. Ovicell (when present) an inflation of the front of the branch
Idmonea atlantica
Zooecia not in regular transverse rows. Ovicell (when present) large, mostly on the back of the branch
Hornera
Branches cylindrical, their ends massive and raised into radial ridges, which carry the orifices
Domopora stellata
Ends of zooecia tubular, arranged all round the branch.
Entalophora
Encrusting Ctenostomata.
Colony entirely adherent, or forming thick, soft, erect lobes
73
Colony erect, well-branched, dark and opaque, resembling seaweed. Zooecia with a long tubular free portion
Anguinella palmata
Orifice large, with two distinct lips. A variable number of stout, brown spines. Encrusting
Flustrella hispida
Orifice small, rounded, borne by a more or less distinct papilla. Encrusting or erect. Zooecia crowded, rarely in single lines.
Alcyonidium
Orifice small, rounded. Zooecia widely separated, connected by narrow tubes
Arachnidium
Zooecia long, less regularly arranged. Polypide with a gizzard.
Bowerbankia(Fig. 238)
Clusters of zooecia very regular, occurring immediately below a bifurcation of the axis. Zooecium with a broad base, not movable.
Amathia lendigera
Zooecia arranged like the pinnules of a leaf, with a constricted base, and movable on the branch
Mimosella gracilis
Main stem zigzag. Branchlets delicate, many ending in sharp points. Zooecia small, ovoid
Vesicularia spinosa
Axis jointed. Zooecia small, in small clusters. Polypide without a gizzard
Valkeria uva, var.cuscuta
Zooecia in whorls, attached to the axis by thread-like stalks, much longer than themselves
Hippuraria egertoni
Zooecia pear-shaped, produced at the lower end into a distinct stalk. Gizzard absent
80
Zooecia not distinctly stalked, although sometimes constricted at the base
81
Stalk long. Zooecium movable on its stalk, compressed, with a membranous area on one side. Twelve or more tentacles. Usually found on Crustacea
Triticella
Stalk variable. Zooecium very transparent; orifice bilabiate. Ten to sixteen tentacles
Farrella repens
Zooecium very small, much elongated and narrow. Eight tentacles.
Valkeria tremula
Zooecia short, minute, with a few short spines on each side of its broadened base. Upper end tubular
Buskia nitens
Zooecia large (about1⁄16inch long), distant, constricted at the base, bearing scattered bristles. Usually found on Crabs or Hydroids.
Avenella fusca
Zooecia tall, cylindrical, not constricted at the base.
Cylindroecium
Zooecia minute. Axis dilating at intervals into swellings, from which new zooecia originate. These may give rise to new stolons, or directly to new zooecia. No gizzard. Found in brackish or fresh water
Victorella pavida
Zooecia long, scattered or in groups. Gizzard present.
Bowerbankia(creeping forms)
It is highly probable that the Ctenostome genusHypophorella[610]will before long be added to the British Fauna. The animal consists of delicate stolons, which give off small zooecia at intervals; and it is known to excavate passages in the substance of the tubes of certain Polychaet worms (ChaetopterusandLanice).
ADDENDUM TO CHAETOGNATHA
Since the Chapter on the Chaetognatha was printed the following list[611]of "The Known Chaetognaths of American Waters" has appeared:—
1.Sagitta elegansVerr. This species resemblesS. bipunctata(videpp.191and193), but differs in size, in the relative proportions of caudal and body segments, and in the presence of diverticula from the intestine.2.Sagitta flaccidaCon. This species resemblesS. hexaptera(videp.193); it is, however, smaller (length, 1.3-1.8 cm.) and has more spines (anterior, 7-8, posterior, 10-12), and its tail segment is relatively smaller.3.Sagitta tenuisCon. Length, 5.25 mm.; hooks, 7-8; anterior spines, 4-5; posterior spines, 7-10.4.Sagitta hispida[612]Con. Length, 7-11 mm.; hooks, 8-9; anterior spines, 4-5; posterior spines, 8-15; tail segment one-third body length; intestine with two diverticula; sensory hairs very numerous.5.Sagitta hexaptera(videp.193).6.Krohnia hamata(videp.194).7.Spadella maximaCon. Length, 5.2 cm.; hooks, 6; anterior spines, 3-5; posterior spines, 5-7; epidermal thickenings round the neck.8.Spadella draco(videp.194).9.Spadella schizoptera[612]Con. An opaque, yellowish-brown species living among algae. Length, 4 mm.; hooks, 8; anterior spines, 4-6; posterior spines wanting. Caudal segment occupies one-half the body length.
1.Sagitta elegansVerr. This species resemblesS. bipunctata(videpp.191and193), but differs in size, in the relative proportions of caudal and body segments, and in the presence of diverticula from the intestine.
2.Sagitta flaccidaCon. This species resemblesS. hexaptera(videp.193); it is, however, smaller (length, 1.3-1.8 cm.) and has more spines (anterior, 7-8, posterior, 10-12), and its tail segment is relatively smaller.
3.Sagitta tenuisCon. Length, 5.25 mm.; hooks, 7-8; anterior spines, 4-5; posterior spines, 7-10.
4.Sagitta hispida[612]Con. Length, 7-11 mm.; hooks, 8-9; anterior spines, 4-5; posterior spines, 8-15; tail segment one-third body length; intestine with two diverticula; sensory hairs very numerous.
5.Sagitta hexaptera(videp.193).
6.Krohnia hamata(videp.194).
7.Spadella maximaCon. Length, 5.2 cm.; hooks, 6; anterior spines, 3-5; posterior spines, 5-7; epidermal thickenings round the neck.
8.Spadella draco(videp.194).
9.Spadella schizoptera[612]Con. An opaque, yellowish-brown species living among algae. Length, 4 mm.; hooks, 8; anterior spines, 4-6; posterior spines wanting. Caudal segment occupies one-half the body length.
Professor Verrill states that the nameS. gracilis(videp.191) was due to a clerical error, the species really referred to beingS. elegans.
A. E. S.
A. E. S.
Every reference is to the page: words in italics are names of genera or species; figures in italics indicate that the reference relates to systematic position; figures in thick type refer to an illustration; f. = and in following page or pages; n. = note.
Every reference is to the page: words in italics are names of genera or species; figures in italics indicate that the reference relates to systematic position; figures in thick type refer to an illustration; f. = and in following page or pages; n. = note.