KEPOKT ON ICIITHYOLOGY. 419 



Girard) appears to be less tangible. As we have not, at jjix'sent, access to the speci- 

 mens on which the latter species are based, we have to rely on the descriptions and 

 figures of their descril)cr. As these are not very satisfoctory, we are prevented from 

 entering" into minute comparison. We can only state that oiu* present species appears 

 to dift'er from the former by the longer head, the shorter nasal barbels, and the absence 

 of true serration on the- posterior f;xce of the dorsal sjiine. With the Idalurits vuIjk's 

 it appears to also disagree by the i)resence of a larger head and a less deeply-forked 

 caudal fin. (^ther differences will doul)tless be found on comjiarison. It may, never- 

 theless, be jiossil)!)- a mere vai-ict\- of the Trfdho-Kn oUvaceus. This can oidy be ascer- 

 tained b}- an autoptical examination. 



Two specimens of this species, not in any essential respect cUfiering from each 

 other, wore (ibtained l)y Dr. Suckle v in the Big Sandy River of Kansas. 



AMIURUS, (Raf.) Gill. 

 Sijnonijmy. 



Ameiurus liaf. Ichtbyologia Ohiensig, p. 6.'). 

 ICTALunrs sp. Eaf. Ichthyologia Ohiensis. 

 PlMELODUS sp. aiict. 



Body moderately elongated, rol)ust, anteriorly vertically ovate and scai'cely com- 

 pressed. Tlie 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. 

 The supra-occipital is extended little posteriorly, and terminates in a more or less acute 

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

 ing the bones is thick. 



r^yes small ()r nidderate. 



Mouth terminal, large, transver.se; uj)j)er jawgenerally [jrojecting l)e\ond the iouer. 



Teeth subulate or acicular, aggregated in broad bands on the intermaxillaries and 

 dentaries. 'I'lic iiircrniaxillary band is convex in front, of equal breadth, and abruptly 

 truncated near the insertion of the maxillaries. Tlie lower dental band is anteriorlv 

 semicircular, attenuated to the angles of the mouth. 



Brancliiostegal niendjrane on each side with from eight to inne rays. 



Dorsal situated over the interval between the ])ectorals and Aentrals, highei- than 

 long, with jpungent sj)inous rav posteriorly dentateil, .nid six branched ones. 



Adi})ose fin short, and inserted over the posterior half of the anal. 



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

 generally provided with from twenty to twenty-five rays. 



The c;iu(!;il till is short, with a margin sometimes convex, and sometimes truncate 

 or scarcely emarginate. 



Ventrals, each with one simple and seven Inanched rays. 



This genus includes our C(^»mnion Eastern American catfishes, and is readily recog- 

 nized by the broad head covenil l)v a thick skin, the free termination of the posterior 

 process of the supra-occipital bone, tlie compressed body, and the slightl}- eniarginatt- 

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



