EEPOET ON ICHTHYOLOGY. 



Girard) appears to be less tangible. As we have not, at present, access t< 



figures of their deseriber. As these are not wry satisfactory, we arc prey 

 entering into minute comparison. We can only state that onr present spec 

 to differ from the former by the longer head, the shorter nasal barbels, and 1 

 of true serration on the posterior face of the dorsal spine. With the Ictat 

 it appears to also disagree by the presence of a larger head and a Less da 

 caudal fin. Other differences will doubtless be found on comparison, it c 

 theless, be possibly a mere variety of the Ittalurus olivaceus. This can on] 

 tained by an autoptical examination. 



Two specimens of this species, not, in any essential respect dilicring 

 other, were obtained by Dr. Buckley in the 1% Sandy Kiver of Kansas. 



AMIUKUS, (Kaf.) Gill. 



Ictalurus sp. Raf. Ichtbyologia Ohfensis. 

 Pimelodus sp. auct. 



Body moderately elongated, robust, anteriorly vertically ovate and scarcely com- 

 pressed. The caudal peduncle is also robust, but much compressed, and at its end 

 equally convex. 



Head large, wide, and laterally expanded; above ovate, and in profile cuneiform. 



point, which is entirely separated from the second interspinal buckler. The skin cover- 

 ing the bones is thick/ 



Eyes small or moderate. 



dentaries. The intermaxillary band is convex in front, of equal breadth, and abruptly 

 truncated near the insertion of the maxillaries. The lower dental band is anteriorly 

 semicircular, attenuated to the angles of the mouth. 



Branchiosteual membrane on each side with from eight to nine rays. 



Dorsal situated over the interval between the pectorals ami ventral*, higher than 

 long, with pungent spinous ray posteriorly dentated, and six branched ones. 



Adipose fin short, and inserted over the posterior half of the anal. 



Anal fin of moderate length, commencing within a short distance of the anus, and 

 generally provided with from twenty to twenty-five rays. 



The caudal fin is short, with a margin sometimes convex, and sometimes truncate 



Ventrals, each v 



This genus inch 



nized by the broad head covered by a thick skin, the free termination of the posterior 

 process'of the supra-occipital bone, the compressed body, and the slightly emarginate 

 or even convex caudal fin, which is not connected with the adipose dorsal. 



