664 FISHES. 



Twenty-Fifth Family — ALErocEPHALiDiE. 



Body loith or without scales; head naked; harhcls none. 

 Margin of the upper javj formed hy the interniaxillaries and 

 niaxillaries, the former leing placed along the upper anterior 

 edge of the latter. Opercidar apparatus complete. Adipose 

 fin none ; the dorsal fin belongs to the caudal jjortion of the 

 vertebral column. Stomach curved, ivithout blind sac ; pyloric 

 appendages in moderate number. Fseudohranchicc ; air-bladder 

 absent. Gill-ope7iings ve7y wide. 



Before the voyage of the " Cliallenger " one species only 

 of this family was known, Alepocepl talus rostratus, a rare fish 

 from the Mediterranean ; now, four genera with seven species 

 are known, and there is no doubt that this family is one of 

 the most characteristic, and will prove to be one of the most 

 generally distributed forms, of the deep-sea. Their vertical 

 range varies between 345 (Xenodermichthys) and 2150 {Bathy- 

 troctes) fathoms. They approach the Salmonoids, but lack 

 invarialjly the adipose fin. Their dentition is very feeble ; 

 their eye large ; bones thin. Coloration black. 



Alepocephalus has thin cycloid scales; a mouth of moderate 

 width, and no teeth on the maxillary. 



Bathytroctes has cycloid scales, a wide mouth, and teeth 

 on the maxillary as well as intermaxillary. 



Platytroctes has small keeled scales and no ventrals. 



Xenodermichthy^S with fine nodules instead of scales. 



Twenty-Sixth Family — Notopterid.e. 



Head and body scaly ; barbels no7ic. Margin of the upper 

 'jaw fo7^med by the interniaxillaries mesially, and by the 

 maxillarics laterally. Opercular apparatus iiicomplete. Tail 

 prolonged, tapering. Adipose fin none. Bor sal short, belonging 

 to the caudal portio7i of the vertebral column ; anal very long. 

 Stomach without blind sac ; two piijloric appendages. Bseudo- 



