CLASSIFICATION.] ICHTHYOLOGY 693 2. Curimatina : Curimatus, Prochilodus, Cienotropus, Hemiodus, Saccodon, Parodon. 3. Citharinina : Citliarinus. 4. Anastomatina : Lcporinus, Anostomus, Rhytiodus. 5. Nannocharacina : Nannoeharax. 6. Te ragonopteriiui : Alestes, Tetragonopterus, Chirodon, Megalo- brycon, Gastropelecus, Piabucina, Scissor, Pseudochaloeus, Aphyo- charax, Chalccus, Brycon, Chalcinopsis, Bryconops, Creagrutus, Chaluinns, Piabuca, Paragouiates, Agoniates, Nannaethiops, and Bryconaethiops. 7. Hijdrocyonina, : Hydrocyon, Cynodon, Anacyrtus, Hystri- colon, Sahninus, Oligosarcus, Xiphorhamphus, Xiphostoma, and Sarcodaces. 8. Distichodontina : Distichodus. 9. Ichlhyborina : Ichtliyborus and Pliago. 10. Crenuchina : Crenuchus and Xenocharax. 11. Scrrasalmonina : Mylesinus, Serrasalmo, Myletes, and Cato- prion. Family 6. Cyprinodontidce. Head and body covered with scales; barbels none. Margin of the upper jaw formed by the intermaxil- laries only. Teeth in both jaws ; upper and lower pharyngeals with cardiform teeth. Adipose fin none ; dorsal fin situated on the hinder half of the body. Stomach without blind sac ; pyloric appendages none. Pseudobranchue none; air-bladder simple, with out ossicula auditus. 1. C. Carnivores: Cyprinodon, Characodon, Fitzroyia, Haplochilus, Fundulus, Linmurgus, Lucania, Rivulus, Cynolebias, Orestias, Jenynsia, Gainbusia, Pseudoxiphophorus, Belonesox, Anableps. 2. C. Limnopkagcc: Pcecilia, Mollienesia, Platvppecilus, Girardinus. Fossil remains are referable to Cyprinodon and Poecilia. Family 7. Heturopygii. Head naked ; body covered with very small scales ; barbels none. Margin of the upper jaw formed by the intermaxillaries. Villiform teeth in the jaws and on the palate. Adipose fin none. Dor.sal fin belonging to the caudal portion of the vertebral column, opposite to the anal. Ventral fins rudimen tary or absent. Vent situated before the pectorals. Stomach caeeal ; pyloric appendages present. Pseudobranchise none ; air- bladder deeply notched anteriorly. Genera : Amblyopsis (Blind-Fish of the Mammoth Cave) and Chologaster. Family 8. Umbridce. Head and body covered with scales ; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially and by the maxillaries laterally. Adipose fin none ; the dorsal fin belongs partly to the abdominal portion of the vertebral column. Stomach siphonal ; pyloric appendages none ; pseudo- branchio? glandular, hidden ; air-bladder simple. One genus : Umbra. Family 9. Scombresocidce. Body covered with scales ; a series of keeled scales along each side of the belly. Margin of the upper jaw formed by the intermaxillaries mesially and by the maxillarie.s laterally. Lower pharyngeals united into a single bone. Dorsal fin opposite the anal, belonging to the caudal portion of the verte bral column. Adipose fin none. Air-bladder generally present, simple, sometimes cellular, without pneumatic duct. Pseudo branchise hidden, glandular. Stomach not distinct from the in testine, which is quite straight, without appendages. Genera: Belone (Gar-Pike), Scombrcsoy, Hcmirhamphus, Ar- rhimphus, Exocoetus (Flying-Fish). Fossil: Holostcus. Family 10. Esocidce. Body covered with scales ; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially .and by the maxillaries laterally. Adipose fin none ; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach without blind sac ; pyloric appendages none. Pseudobranchiae glandular, hidden ; air-bladder simple ; gill-opening very wide. One genus only : Esox (Pike). Family 11. Galaxiidcv Body naked; barbels none. Margin of the upper jaw chiefly formed by the intermaxillaries, which are short, and continued by a thick lip, behind which are the maxil laries. Belly rounded ; adipose fin none ; dorsal opposite to anal. Pyloric appendages in small number. Air-bladder large, simple ; pseudobranchiiE none. The ova fall into the cavity of the abdomen before exclusion. Genera : Galaxias and Ncochanna. Family 12. Jformyridee.lHody and tail scaly ; head scaleless ; barbels none. The margin of the upper jaw is formed in the middle by the intermaxillaries, which coalesce into a single bone, and laterally by the maxillaries. Suboperculum and interopercu- lum present, the latter very small. On each side of the single parietal bone a cavity leading into the interior of the skull, and covered with a thin bony lamella. All the fins are well developed (Mormyrus) ; or caudal, anal, and ventral fins are absent (Gym- narcfnis). No adipose fin. Pseudobranchiae none ; gill-openings reduced to a short slit. Air-bladder simple. Two caeca pylorica behind the stomach. Genera : Mormyrus and Gymnarchus. Family 13. Stcrnopii/chidcr.. Body naked, or with very thin deciduous scales ; barbels none. Margin of the upper jaw formed by the maxillary and intermaxillary, both of which are toothed ; opercular apparatus not completely developed. Gill-opening very wide ; pseudobranchiae present or absent ; air-bladder simple, if present. Adipose fin present, but generally rudimentary. Series of phosphorescent bodies along the lower parts. The eggs are enclosed in the sacs of the ovaritim, and excluded by oviducts. Genera : Sternoptyx, Argyropelccus, Polyipnus, Coccia, Muuro- licus, Ckauliodus, Gonostoma, Photichthys, and Itiplophos. Family 14. Stomiatidce. Skin naked, or with exceedingly delicate scales ; a hyoid barbel. Margin of the upper jaw formed by the intermaxillary and maxillary, which are both toothed ; opercular apparatus but little developed. Gill-opening very wide ; pseudo- branchire none. The eggs are enclosed in the sacs of the ovarium, and excluded by oviducts. Genera : Astroncsthes, Stomias, Echiostoma, Malacostcus, and Bathyophis. Family 15. Salmonidce. Body generally covered with scales ; head naked ; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially and by the maxillaries laterally. Belly rounded. A small adipose fin behind the dorsal. Pyloric appendages generally numerous, rarely absent. Air-bladder large, simple ; pseudobranchiae present. The ova fall into the cavity of the abdomen before exclusion. Genera : Salmo (Salmon, Trout, Chan ), Oncorhynchus, Brachy- mystax, Luciotrutta, Plccoglossus, Osmcrus (Smelt), Rctropinna, Hypomcsus, Thalcichtliys, Mallotus (Capelin), Corcgonus (Gwyniad, Pollan), Thymallus (Grayling), Salanx, Argentina, Microstuma, Bathylagus. Fossil : Osmeroidcs, Acrognathus, and Aulolepis. Family 16. Pcrco2)sidcc. Body covered with ctenoid scales ; head naked. Margin of the upper jaw formed by the intermaxilluries only; opercular apparatus complete. Barbels none. Gill-openings wide. Adipose fin present. One genus only : Percopsis. Family 17. Jfaplochitonidai.Tiody naked or scaly (cycloid). Margin of the upper jaw formed by the intermaxillary ; opercular apparatus complete. Barbels none. Gill-opening wide ; pseudo- branchiae. Air-bladder simple. Adipose fin present. Ovaries laminated ; the eggs fall into the cavity of the abdomen, there being no oviduct. Pyloric appendages none. Genera : HaplocTiiton and Prototrodcs. Family 18. Gonorhynchidcc. Head and body entirely covered with spiny scales ; mouth with barbels. Margin of the upper jaw formed by the intermaxillary, which, although short, is continued downwards as a thick lip, situated in front of the maxillary. Adi pose fin none ; the dorsal fin is opposite to the ventrals, and short, like the anal. Stomach simple, without blind sac ; pyloric appen dages in small number. Pseudobranchise ; air-bladder absent. Gill-openings narrow. One genus only : Gonorlujncliua. Family 19. Hyodontidce. Body covered with cycloid scales; head naked ; barbels none. Margin of the upper jaw formed by the intermaxillaries mesiully and by the maxillaries laterally, the latter being articulated to the end of the former. Opercular appa ratus complete. Adipose fin none ; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach horseshoe-shaped, without blind sac; intestine short; one pyloric appendage. Fseudo- branchire none ; air-bladder simple. Gill-openings wide. The ova fall into the abdominal cavity before exclusion. One genus only : Hyodon (Moon-Eye). Family 20. Pnntodontidcc. Body covered with large cycloid scales ; sides of the head osseous. Margin of the upper jaw formed by the single intermaxillary mesially and by the maxillaries laterally. The dorsal fin belongs to the caudal portion of the verte bral column, is short, and opposite and similar to the anal. Gill- openings wide ; gill-covers consisting of a proeoperculum and oper- culum only. Branchiostegals numerous. Pseudobranchise none ; air-bladder simple. Stomach without caecal sac ; one pyloric ap pendage. Sexual organs with a duct. One genus : Panf.odon. Family 21. Ostcoglossidcc. Body covered with large hard scales, composed of pieces like mosaic. Head scaleless ; its integuments almost entirely replaced by bone ; lateral line composed of wide openings of the mucous duct. Margin of the upper jaw formed by the intermaxillaries mesially and by the maxillaries laterally. The dorsal fin belongs to the caudal portion of the vertebral column, is opposite and very similar to the anal fin ; both approximate to the rounded caudal (with which they are abnormally confluent). Gill- openings wide ; pseudobranchise none ; air-bladder simple or cellu lar. Stomach without caecal sac ; pyloric appendages two. Genera : Ostcoglossum, Arapaima, and Heterolis. Family 22. Clupeidcc. Body covered with scales ; head naked; barbels none. Abdomen frequently compressed into a serrated ed^e. Margin of the upper jaw formed by the intermaxillaries mesially and by the maxillaries laterally ; maxillaries composed of at least three" movable pieces. Opercular apparatus complete. Adipose fin none ; dorsal not elongate ; anal sometimes very long.
Stomach with a blind sac ; pyloric appendages numerous. Gill-
