Cope.] 488 [June 7, 
greater width of its head, and the gape of the mouth, together with the 
decided but shallow furcation of the caudal fin. The barbels are consider- 
ably shorter than in any other species of the fork-tailed section. 
Head and dorsal region very flat, the width of the former contained 3.5 
times in the length of the body and head, and the length of the same en- 
tering the same three times. The depth at the first dorsal ray, enters the 
same 5.4 times. That ray is exactly intermediate between the end of the 
muzzle and the posterior margin of the base of the adipose, having thus 
a more posterior position than in A. lynx, where it measures the middle 
of a line terminating at the anterior base of that fin. The free extremity 
of the adipose is in line with the same of the anal. Radii DI.6; A. II, 
19; V.8. The eye is small, its long diameter entering the length of the 
head, measured on the middle line above, seven times, and six times in 
interorbital space. Pectoral spine weakly ; dorsal not, serrate. Humeral 
process strongly rugose to near extremity. 
Maxillary barbel reaching two-thirds to three-fourths the distance from 
its base to the upper part of the branchial slit, the outer only half way to 
the branchiostegal margin, the innerthree-fourths the length of the outer. 
The extremity of the muzzle is regularly rounded, the upper jaw project- 
ing a little beyond the upper. Branchiostegal rays nine. Total length 
eighteen inches ;. length dorsal spine 18 lin.; do. pectoral spine 18 lin.; do. 
basis of anal 85 lin.; width of head 53 1. 
Color abeve lava ; lower surfaces, ineluding lower lip, (yellow or) 
white in alcohol ; mental beards white. 
This species is nearest the A. lynx, Girard, whieh inhabits the same 
rivers, but is readily distinguished as above pointed out, and in addition 
by the shorter barbels and lower body. In the width of its gape it 
exceeds any other North American cat-fish, and will allow of a remote 
comparison. with Lophius in this respect. 
I obtained three specimens in the Washington, D. C., market, which 
came from the lower course of the Potomac river. It occurs in the other 
tributaries of the Chesapeake Bay, and I think I haveseen it in the market 
of Baltimore. I have not yet observed it in Philadelphia. In the former 
cities it is deservedly esteemed for the table, and is more valuable than 
the A. lynx and A. nebulosus, on aecount of its superior size. 
The last named fish is sold in Philadelphia and neighborhood. It often 
attains a foot in length. I cannot distinguish the Pim. albidus, Lesueur. 
Pale and piebald varieties of the fish oecur. 
79. AMIURUS NIVEIVENTRIS, Cope. 
Spec. nov. 
This fish presents a great contrast to the last, resembling in fact the 
Ictalurus cerulescens, Raf., in its slender proportions. 
Width of head 4.75 times in length, exclusive of caudal fin. Orbit nearly 
four times into interorbital width. Depth 5.22 in length as above. Dor- 
sal spine three inches from end muzzle, 3.5 inches from origin adipose fin ; 
its posterior margin with a concealed serration. Pectoral spine strongly 
