132 MEMOIRS OF THE CARNEGIE MUSEUM 



zz. Head depressed, its width at the mouth about equal to its greatest 

 width. Adipose fin shorter than the anal; caudal forked, the 

 rays much branched. Maxillary band of teeth much narrowed 

 in the middle; teeth on the vomer separated on the median 

 line, closely joined to the palatine patches, together forming, 

 on either side, a figure somewhat like a comma. Top of head 

 osseous; the occipital process produced, meeting or nearly 

 meeting the dorsal plate; fontanel extending from the middle 

 of the snout to behind the eyes, and continued to the occipital as 



a groove Pseudoplatystoma. 



aa. Gill-membranes united and joined to the isthmus; nares remote, without barbels. 

 A. A series of bony plates along the sides. (Dorndinoe.) 



B. Eye small, in anterior portion of head; snout depressed; teeth well-developed; humeral 

 process much longer and stronger than the coracoid process; anterior nares near the 



upper lip Doras. 



BB. Eye in middle or behind the middle of the head. 



C. Barbels all simple, teeth none Oxydoras. 



CC. Maxillary and mental barbels fringed. 



D. Teeth none; a single large pectoral pore Leptodoras. 



DD. Teeth in one or both jaws; numerous pectoral pores Hemidoras. 



A A. No plates along the sides. 



E. Maxillary and mental barbels present. (Auchenipterince.) 



F. Mental barbels in two pairs. Adipose fin shorter than the anal fin. 



G. Anal short, 7-11; mouth terminal; jaws equal; caudal forked; V. 6. . . Centromochlus. 

 GG. Anal 19-41. 



//. Caudal obliquely truncate or slightly emarginate; outer margin of pectoral 

 spine serrate; mouth terminal, jaws equal or the lower longer; no promi- 

 nent bony orbit. V. 6-10, A. 19-40 Trachycorystes. 



////. Caudal deeply forked; outer margin of pectoral spine smooth or granular. 



V. 8; A. 17-21 Pseudauchenipterus. 



FF. Mental barbels arranged in a series near the symphysis; adipose fin short; dorsal fin 



well-developed, 1,6. Teeth villiform. V. 12-15 Auchenipterus. 



EE. Maxillary barbels only. (Ageneiosince.) 



I. Air-bladder projecting into the abdominal cavity, naked laterally, the skin over it 

 forming a large pseudo-tympanum; snout short, about equal to the eye. 



Tympanopleura. 



//. Air-bladder minute, concealed under peritoneum and largely covered with bone; no 



pseudo-tympanum. Snout much longer than eye Ageneiosus. 



Subfamily Ariin^e. 

 Felichthys Swainson. 10 



10 A specimen of Felichthys 295 mm. long marked filamentosus is in the Leiden Museum, from Ind. 

 Occid., probably collected by Schomburgk. 



Dorsal from snout 3 in the length; highest anal ray 6+ in the length, base of anal 7; pectoral 

 spine 4 in the length, dorsal spine 4.8; anal lobe with numerous black dots; A. 19; distance of adipose 

 from dorsal 2.6 in the length. This specimen would therefore be bahiensis. 



