10 CALIFORNIA ACADEMY OF SCIENCES. 



dd. Teeth villiform, in bands. Pimelodince. 



fia. Gill membranes united and joined to the isthmus; nares remote, with- 

 out barbels. 



e. Air bladder lying free in the abdominal cavity; mallei turned 

 outward behind, their tips greatly expanded, forming the ante- 

 rior wall of the single air bladder; modified vertebrae with- 

 out lateral processes. 



/. A series of bony plates along the sides. Doradmw. 



ff. Sides naked. Auchenipterince. 



ee. Air bladders vestigiary, almost wholly surrounded by bone, 

 one on either side of the centrum of the modified vertebrae. 

 Lateral processes of the modified vertebras well developed. 



Ageneiosince. 



aa. Air bladder vestigiary, one on either side of the 

 coalesced vertebrae and entirely surrounded by a bony 

 capsule. 



e. Air bladder enclosed in a capsule formed by 

 the lateral processes of the coalesced vertebrae, 

 by the scapula, and by the process connect- 

 ing the scapula with the basi occipital; the 

 external opening of the air bladder capsule 

 bounded by the scapula and lateral processes, 

 its anterior side open. Adipose fin present, 

 dorsal on anterior half of body over the anal 

 which is scarcely shorter than the caudal 

 portion of the vertebral column. Gill mem- 

 branes entirely free from the isthmus. 

 Nares without barbels. Derm naked. ''Dia- 

 phragm" membranaceous. 



HYPOPHTHALMID^E iv. 



ee. Air bladder enclosed in a capsule formed by 

 the lateral processes of the coalesced verte- 

 brae only; the external orifice of the air 

 bladder capsule as in Hypophthalmidce, its 

 anterior side closed. Adipose fin none; dor- 

 sal usually on the caudal, sometimes on the 

 abdominal portion of the vertebral column; 



