664 FISHES. 



Twenty-Fifth Family — ^Alepocephalid^. 



Body with or luithout scales; head naked; harbels none. 

 Margin of the upper jaw formed hy the intermaxillaries and 

 maxillaries, the former being placed along the upper anterior 

 edge of the latter. Opercular apparatus complete. Adipose 

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

 vertebral column. Stomach curved, without blind sac ; pyloric 

 appendages in moderate number. Pseudobranchioe ; air-bladder 

 absent. Gill-openings very wide. 



Before tlie voyage of the " Challenger " one species only 

 of this family was known, Alepocephalus rostratus, a rare fish 

 from the Mediterranean ; now, four genera with seven species 

 are known, and there is ho 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 

 invariably 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 maxiUary. 



Bathyteoctes has cycloid scales, a wide mouth, and teeth 

 on the maxillary as well as intermaxillary. 



Platytroctes has small keeled scales and no ventrals. 



Xenodermichthys with fine nodules instead of scales. 



Twenty-Sixth Family — Notoptekid^. 



Head and body scaly ; barbels none. Margin of the upper 

 jaw formed by the inte^'maxillaries mesially, and by the 

 maxillaries laterally. Opercular apparatus incomplete. Tail 

 prolonged, tapering. Adipose fin none. Dorsal short, belonging 

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

 Stomach without blind sac ; two pyloric appendages. Pseudo- 



