Head-s"ield, dor"al, ofOstreostraci,327,348Head-s"ield, dor"al, ofPalæostracan,348Head-s"ield, dor"al, ofPteraspis,29Head-s"ield, dor"al, ofThyestes,29,31,327,332,338,340,341,348Head-s"ield,ventral, Scaphaspis,349Heart, nerves,2,447Her"t,origin of vertebrate,179,451,459Her"t,relative position in vertebrate and invertebrate,175Her"t,veins forming vertebrate,180Hemiaspis,24,25,249,250,351,414Hemispheres, cerebral,47Hepatopancreas of Ammocœtes,452Hepatop"ncreas ofLimulus,211Heterostraci,29,275,326,343Hirudinea,478Histolysis in transformation of the lamprey,59Homology of branchial region of vertebrate and invertebrate,149Homol"gy ofductless glands and nephridial organs,418Homol"gy ofexternal genital ducts of arthropods and nephridia of annelids,429Homol"gy ofgerminal layers in allMetazoa,459Homol"gy ofpituitary body of Ammocœtes and coxal glands of Limulus,319Homol"gy oftubular muscles of Ammocœtes and veno-pericardial muscles of Limulus,309Homol"gy ofventral aorta of vertebrate and longitudinal venous sinuses of Limulus,178Hydra,441,465,472,476Hydrophilus larva, eye,84Hyoid segment in Ammocœtes,186,267Hypoblast,434,438,444,445,459Hypoctonus, cartilage cells in entosternite,133Hypo"tonus,operculum,189,207Hypogastric plexus,3Hypogeophis,393Hypophysis,229,244,317,318,340Infundibulum, position,122,132Infun"ibulum,tube, the ancestral œsophagus,4,37,244,318Infun"ibulum, tu"e,relation to neural canal,14,36,318,440,457Infun"ibulum, tu"e, relati"n tonotochord,318,435,440Infun"ibulum, tu"e, relati"n toolfactory tube,220,228,318,340Insects, chordotonal organs,364,370Invertebrate, heart,175,179Invert"brate,excretory organs,418Invert"brate,nervous system,13,54Invert"brate,segmental nerves,152Keraspis,75,328,338Kidney,420,459,476Kid"ey,nerves,477King-crab,v.LimulusLabyrinthodont,21,28Lamina terminalis,49Lamprey,v.Ammocœtes and PetromyzonLarva,v.Transformation of the LampreyLateral line system,261,355,411,470Law of Progress,19Lw"ofRecapitulation,434,456,498Layer, germinal,459Lay"r,laminated,347,348Leech,421Lens, formation,83,115Lepidosiren,148,461,466Limulus or king-crab,25,140,236,240Liml"usappendages, branchial,138,164,175Liml"usappendages, prosomatic,381Liml"usbrain,54Liml"uscirculation,174,176Liml"usclassification,26,249Liml"uscœlomic cavities,252,328Liml"uscoxal glands,321,389,397,403,429Liml"useyes, median,62,74,81Liml"usentosternite or plastron,142,143Liml"usflabellum,360,362,363,380,381Liml"usgenerative organs and ducts,189,202,208,209,380Liml"usheart,180Liml"usmusculature, branchial,170Liml"us muscl"ature,prosomatic,247Liml"us muscl"ature,veno-pericardial,177,297,309,313Liml"usnerves, appendage,140,157Liml"us ner"es,cardiac,314Liml"us ner"es,segmental, tripartite division of,157,235,267,355Liml"ussegments, branchial,152Liml"us segm"nts,first mesosomatic,188Liml"us segm"nts,prosomatic,233Liml"usoperculum,189,202,235,295Liml"ussense-organs, poriferous, of appendages,359Lip, lower, of Ammocœtes,246,289,297,458Li",upper,of Am"ocœtes,228,243,303,336Liver, Ammocœtes,452Liv"r,Limulus,209,211Lizard, pineal eye,80Liz"rd,suprarenals,424Liz"rd,tail,50Lobes, optic,101Lobster,489Lungs,148Lung-books of scorpions,150Lymph,474Lymph-corpuscles,463,490Lymphocytes,472Malapterurus,470Mammal, dominance of,21Man, dominance of,17Marsipobranchs,23,35Medullation of nerve-fibres,20,267,467,477Membranes, basement,436Meroblastic egg,485Merostomata,25,249,321Mesencepalon,48Mesoblast,444,455,459Mesoglœa,474Mesonephros,389,400,424,429Mesosoma,52Mesothelium,472,477Metanephros,389Metasoma,52,387,411Metastoma,239,246,272,289,342,458Metazoa,444,459,471,472Meynert's bundle,48,77Mollusca, dominance of,23Mouth, old, or palæostoma,14,317,322,440,458Mo"th,vertebrate,317Muco-cartilage,v.CartilageMuscles, antagonistic,447Mus"les,branchial,170Mus"les,connection of, with central nervous system,464Mus"les,eye, and their nerves,263Mus"les,prosomatic,243,247Mus"les,phylogeny of origin of skeletal,478Mus"les,rudimentary, in Ammocœtes,289Mus"les,somatic trunk, origin of,406Mus"les,striated,20,155Mus"les,tubular, of Ammocœtes,309Mus"les,unstriped,20,447,491Mus"les,visceral and parietal,155,172Mus"les,veno-pericardial of Limulus and Scorpion,177,297,309Muscle-spindles,267Mygalidæ, stomach,109Mygl"idæ,segmentation,249,306Myomeres,262,337,414,479Myotomes,332,337,338,391,407,408Mysis, eyes,100My"is,ductless glands,422Myxine,220,392,402,419Nebalia,144,422Nemertina,475Nephridia,395,421,429Nephrocœle,430Nephrotome,393Nerves, abducens,155,263,266Ner"es,auditory,356,376Ner"es,autonomic,3Ner"es,facial,155,156,186,188,192,311,356,378Ner"es, fa"ial,ramus branchialis profundus,311Ner"es,to flabellum, in Limulus,361,375Ner"es,glossopharyngeal,155,156,186,356Ner"es,hypoglossal,156Ner"es,inhibitory,447Ner"es,inedullation of,20,267,467,477Ner"es,occulomotor,155,234,263,274Ner"es,olfactory,229Ner"es,optic,101,104Ner"es, ot"ic,of pineal eye,79Ner"es,origin of ganglia of cranial and spinal,281Ner"es,to pecten of Scorpion,375,376Ner"es,preganglionic,2Ner"es,of prosoma in Limulus,235,355Ner"es,regeneration of,469Ner"es,roots, of Limulus,157Ner"es,sacral,448Ner"es,segmental,152,156Ner"es,segmental nature of cranial,259,411Ner"es,spinal, absence of lateral roots in,388Ner"es,spinal accessory,154Ner"es,trigeminal,151,155,156,234,243,257,279Ner"es, trigm"inal,motor nucleus of,280Ner"es, trigm"inal,of Ammocœtes,288Ner"es,tripartite arrangement of cranial nerves,154,157,235,267,355Ner"es,trochlear,48,155,234,263,276Ner"es,vagus,151,154,156,173,186,356,447,449Nervous system, central, comparison of Vertebrate and Arthropod,36,457Nervous"ystem, ce"tral,connection of, with muscular and epithelial tissues,464Nervous"ystem, ce"tral, conne"tion of,with retina,71Nervous"ystem, ce"tral,disease of,50Nervous"ystem, ce"tral,evidence of,8Nervous"ystem, ce"tral,evolution of,34Nervous"ystem, ce"tral,importance of,16,463,482,498Nervous"ystem, ce"tral,invertebrate,10,13,54Nervous"ystem, ce"tral,origin of,480Nervous"ystem, ce"tral,relation of germ-band to,483Nervous"ystem, ce"tral,segmentation of vertebrate,51Nervous"ystem, ce"tral,tube of,36-51,102,211,433,455,457Nervous"ystem, ce"tral,vertebrate,10,13,40,41,152Nervous"ystem,enteric,447Nervous"ystem,sympathetic,2,424,428,448,491Neurenteric canal,37Neuroblast,465Neuromeres,55,247,262,312,316Neurones,72,92,465Neuropil,71,91Neuropore,220,457Nose,219No"e,of Osteostraci,329,352,458Notochord,120,122,180,181,220,244,295,318,405,417,433,436,494Ocelli,70Œsophagus of Ammocœtes,405Œsop"agus ofArthropod, compared to tube of infundibulum,4,244,440Olfactory apparatus, evidence of the,218Olfa"toryorgans of the Scorpion group,220Olfa"torytube of Ammocœtes,219,225,244,317Oligochæta,421,478Operculum of Eurypterus,191,212,291Operc"lum ofLimulus,189,202,235,295Operc"lum ofPhrynus,191Operc"lum ofScorpion,189,206,212,372Operc"lum ofThelyphonus,189,190,206Organs, arrangement of,10Org"ns,auditory, of arachnids and Insects,368Org"ns,branchial, innervation of vertebrate,151Org"ns, bran"hial,sense-organs of embryo vertebrate,261,281Org"ns,chordotonal, of insects,364,369,370Org"ns,electric,470Org"ns,generative, of Limulus,208,209Org"ns, gener"tive,connection between Thyroid gland and,215Org"ns,genital, of sea-scorpions,206Org"ns,lateral line,355,411Org"ns,lyriform, of arachnids,364,369Org"ns,olfactory, of Scorpion group,220Org"ns,phagocytic,420Org"ns,racquet, of Galeodes,369,375Org"ns,segmental excretory,389,391,408,418,459,477Org"ns,sense, of appendages of Limulus,358Org"ns,vestigial,456Org"ns,of vision, evidence of,68
Head-s"ield, dor"al, ofOstreostraci,327,348
Head-s"ield, dor"al, ofPalæostracan,348
Head-s"ield, dor"al, ofPteraspis,29
Head-s"ield, dor"al, ofThyestes,29,31,327,332,338,340,341,348
Head-s"ield,ventral, Scaphaspis,349
Heart, nerves,2,447
Her"t,origin of vertebrate,179,451,459
Her"t,relative position in vertebrate and invertebrate,175
Her"t,veins forming vertebrate,180
Hemiaspis,24,25,249,250,351,414
Hemispheres, cerebral,47
Hepatopancreas of Ammocœtes,452
Hepatop"ncreas ofLimulus,211
Heterostraci,29,275,326,343
Hirudinea,478
Histolysis in transformation of the lamprey,59
Homology of branchial region of vertebrate and invertebrate,149
Homol"gy ofductless glands and nephridial organs,418
Homol"gy ofexternal genital ducts of arthropods and nephridia of annelids,429
Homol"gy ofgerminal layers in allMetazoa,459
Homol"gy ofpituitary body of Ammocœtes and coxal glands of Limulus,319
Homol"gy oftubular muscles of Ammocœtes and veno-pericardial muscles of Limulus,309
Homol"gy ofventral aorta of vertebrate and longitudinal venous sinuses of Limulus,178
Hydra,441,465,472,476
Hydrophilus larva, eye,84
Hyoid segment in Ammocœtes,186,267
Hypoblast,434,438,444,445,459
Hypoctonus, cartilage cells in entosternite,133
Hypo"tonus,operculum,189,207
Hypogastric plexus,3
Hypogeophis,393
Hypophysis,229,244,317,318,340
Infundibulum, position,122,132
Infun"ibulum,tube, the ancestral œsophagus,4,37,244,318
Infun"ibulum, tu"e,relation to neural canal,14,36,318,440,457
Infun"ibulum, tu"e, relati"n tonotochord,318,435,440
Infun"ibulum, tu"e, relati"n toolfactory tube,220,228,318,340
Insects, chordotonal organs,364,370
Invertebrate, heart,175,179
Invert"brate,excretory organs,418
Invert"brate,nervous system,13,54
Invert"brate,segmental nerves,152
Keraspis,75,328,338
Kidney,420,459,476
Kid"ey,nerves,477
King-crab,v.Limulus
Labyrinthodont,21,28
Lamina terminalis,49
Lamprey,v.Ammocœtes and Petromyzon
Larva,v.Transformation of the Lamprey
Lateral line system,261,355,411,470
Law of Progress,19
Lw"ofRecapitulation,434,456,498
Layer, germinal,459
Lay"r,laminated,347,348
Leech,421
Lens, formation,83,115
Lepidosiren,148,461,466
Limulus or king-crab,25,140,236,240
Liml"usappendages, branchial,138,164,175
Liml"usappendages, prosomatic,381
Liml"usbrain,54
Liml"uscirculation,174,176
Liml"usclassification,26,249
Liml"uscœlomic cavities,252,328
Liml"uscoxal glands,321,389,397,403,429
Liml"useyes, median,62,74,81
Liml"usentosternite or plastron,142,143
Liml"usflabellum,360,362,363,380,381
Liml"usgenerative organs and ducts,189,202,208,209,380
Liml"usheart,180
Liml"usmusculature, branchial,170
Liml"us muscl"ature,prosomatic,247
Liml"us muscl"ature,veno-pericardial,177,297,309,313
Liml"usnerves, appendage,140,157
Liml"us ner"es,cardiac,314
Liml"us ner"es,segmental, tripartite division of,157,235,267,355
Liml"ussegments, branchial,152
Liml"us segm"nts,first mesosomatic,188
Liml"us segm"nts,prosomatic,233
Liml"usoperculum,189,202,235,295
Liml"ussense-organs, poriferous, of appendages,359
Lip, lower, of Ammocœtes,246,289,297,458
Li",upper,of Am"ocœtes,228,243,303,336
Liver, Ammocœtes,452
Liv"r,Limulus,209,211
Lizard, pineal eye,80
Liz"rd,suprarenals,424
Liz"rd,tail,50
Lobes, optic,101
Lobster,489
Lungs,148
Lung-books of scorpions,150
Lymph,474
Lymph-corpuscles,463,490
Lymphocytes,472
Malapterurus,470
Mammal, dominance of,21
Man, dominance of,17
Marsipobranchs,23,35
Medullation of nerve-fibres,20,267,467,477
Membranes, basement,436
Meroblastic egg,485
Merostomata,25,249,321
Mesencepalon,48
Mesoblast,444,455,459
Mesoglœa,474
Mesonephros,389,400,424,429
Mesosoma,52
Mesothelium,472,477
Metanephros,389
Metasoma,52,387,411
Metastoma,239,246,272,289,342,458
Metazoa,444,459,471,472
Meynert's bundle,48,77
Mollusca, dominance of,23
Mouth, old, or palæostoma,14,317,322,440,458
Mo"th,vertebrate,317
Muco-cartilage,v.Cartilage
Muscles, antagonistic,447
Mus"les,branchial,170
Mus"les,connection of, with central nervous system,464
Mus"les,eye, and their nerves,263
Mus"les,prosomatic,243,247
Mus"les,phylogeny of origin of skeletal,478
Mus"les,rudimentary, in Ammocœtes,289
Mus"les,somatic trunk, origin of,406
Mus"les,striated,20,155
Mus"les,tubular, of Ammocœtes,309
Mus"les,unstriped,20,447,491
Mus"les,visceral and parietal,155,172
Mus"les,veno-pericardial of Limulus and Scorpion,177,297,309
Muscle-spindles,267
Mygalidæ, stomach,109
Mygl"idæ,segmentation,249,306
Myomeres,262,337,414,479
Myotomes,332,337,338,391,407,408
Mysis, eyes,100
My"is,ductless glands,422
Myxine,220,392,402,419
Nebalia,144,422
Nemertina,475
Nephridia,395,421,429
Nephrocœle,430
Nephrotome,393
Nerves, abducens,155,263,266
Ner"es,auditory,356,376
Ner"es,autonomic,3
Ner"es,facial,155,156,186,188,192,311,356,378
Ner"es, fa"ial,ramus branchialis profundus,311
Ner"es,to flabellum, in Limulus,361,375
Ner"es,glossopharyngeal,155,156,186,356
Ner"es,hypoglossal,156
Ner"es,inhibitory,447
Ner"es,inedullation of,20,267,467,477
Ner"es,occulomotor,155,234,263,274
Ner"es,olfactory,229
Ner"es,optic,101,104
Ner"es, ot"ic,of pineal eye,79
Ner"es,origin of ganglia of cranial and spinal,281
Ner"es,to pecten of Scorpion,375,376
Ner"es,preganglionic,2
Ner"es,of prosoma in Limulus,235,355
Ner"es,regeneration of,469
Ner"es,roots, of Limulus,157
Ner"es,sacral,448
Ner"es,segmental,152,156
Ner"es,segmental nature of cranial,259,411
Ner"es,spinal, absence of lateral roots in,388
Ner"es,spinal accessory,154
Ner"es,trigeminal,151,155,156,234,243,257,279
Ner"es, trigm"inal,motor nucleus of,280
Ner"es, trigm"inal,of Ammocœtes,288
Ner"es,tripartite arrangement of cranial nerves,154,157,235,267,355
Ner"es,trochlear,48,155,234,263,276
Ner"es,vagus,151,154,156,173,186,356,447,449
Nervous system, central, comparison of Vertebrate and Arthropod,36,457
Nervous"ystem, ce"tral,connection of, with muscular and epithelial tissues,464
Nervous"ystem, ce"tral, conne"tion of,with retina,71
Nervous"ystem, ce"tral,disease of,50
Nervous"ystem, ce"tral,evidence of,8
Nervous"ystem, ce"tral,evolution of,34
Nervous"ystem, ce"tral,importance of,16,463,482,498
Nervous"ystem, ce"tral,invertebrate,10,13,54
Nervous"ystem, ce"tral,origin of,480
Nervous"ystem, ce"tral,relation of germ-band to,483
Nervous"ystem, ce"tral,segmentation of vertebrate,51
Nervous"ystem, ce"tral,tube of,36-51,102,211,433,455,457
Nervous"ystem, ce"tral,vertebrate,10,13,40,41,152
Nervous"ystem,enteric,447
Nervous"ystem,sympathetic,2,424,428,448,491
Neurenteric canal,37
Neuroblast,465
Neuromeres,55,247,262,312,316
Neurones,72,92,465
Neuropil,71,91
Neuropore,220,457
Nose,219
No"e,of Osteostraci,329,352,458
Notochord,120,122,180,181,220,244,295,318,405,417,433,436,494
Ocelli,70
Œsophagus of Ammocœtes,405
Œsop"agus ofArthropod, compared to tube of infundibulum,4,244,440
Olfactory apparatus, evidence of the,218
Olfa"toryorgans of the Scorpion group,220
Olfa"torytube of Ammocœtes,219,225,244,317
Oligochæta,421,478
Operculum of Eurypterus,191,212,291
Operc"lum ofLimulus,189,202,235,295
Operc"lum ofPhrynus,191
Operc"lum ofScorpion,189,206,212,372
Operc"lum ofThelyphonus,189,190,206
Organs, arrangement of,10
Org"ns,auditory, of arachnids and Insects,368
Org"ns,branchial, innervation of vertebrate,151
Org"ns, bran"hial,sense-organs of embryo vertebrate,261,281
Org"ns,chordotonal, of insects,364,369,370
Org"ns,electric,470
Org"ns,generative, of Limulus,208,209
Org"ns, gener"tive,connection between Thyroid gland and,215
Org"ns,genital, of sea-scorpions,206
Org"ns,lateral line,355,411
Org"ns,lyriform, of arachnids,364,369
Org"ns,olfactory, of Scorpion group,220
Org"ns,phagocytic,420
Org"ns,racquet, of Galeodes,369,375
Org"ns,segmental excretory,389,391,408,418,459,477
Org"ns,sense, of appendages of Limulus,358
Org"ns,vestigial,456
Org"ns,of vision, evidence of,68