SILURIDA. — XXIV. 39 
35. TACHYSURUS Lacépede. (Galeichthys and Arius Cuv. 
& Val.) (rays, swift ; ovpa, tail.) 
a. Teeth all pointed; top of head with a bony occipital shield which is not 
covered by skin; bands of palatine teeth without backward prolongation 
on the median line; vomerine bands of teeth not confluent; ante-dorsal 
shield small, crescent-shaped; eyes well above angle of mouth; species 
with blue lustre in life. (Arzopsis Gill.) 
49, T. felis (L.). Sea Cart-Fisu. Interorbital area flattish 
and smooth, without ridges or granulations; fins not low, the 
spines more than half length of head; vomerine teeth in a small 
patch; palatine teeth in a larger one, on each side, the four 
patches separate ; fontanelle prolonged backward as a narrow 
groove; occipital process long, about 4 head, convex at tip, with 
a median keel; gill membranes not meeting at an angle; maxillary 
barbel nearly as long as head. L.24. N.Y. to Mexico; common 
S. (Lat., cat.) 
36. ICTALURUS Rafinesque. (iyOvs, fish ; atAovpos, cat.) 
a. Anal fin very long; its rays 32 to 35; its base nearly 3 of body. 
50. I. furcatus (Cuv. & Val.). CHUCKLE-HEADED Cat. Silvery, 
nearly plain; eye small, wholly before middle of head; head 44; 
depth 5. Miss. valley, not uncommon. (Lat., forked.) 
aa. Anal fin moderate; its rays 24 to 30; its base 3} to 4 in body. 
51. I. punctatus (Rafinesque). CmANNEL Cat. WHITE Cart. 
Strver Cart. Olivaceous, rarely blackish, the sides silvery, al- 
most always with small round dark olive spots; eye large, not 
wholly in front of middle of head; mouth small; barbels long ; 
spines strong, serrate; head 4; depth 5. L.3 feet. Montana to 
Vt., Ga., and Mexico, very abundant in flowing streams. <A hand- 
some fish, the best in the family as food. (Lat., spotted.) 
37. AMEIURUS Rafinesque. (a privative; pelovpos, curtailed, 
the tail not notched.) 
a. Caudal fin forked (species approaching Jctalurus). 
b. Anal rays 25 to 35; humeral process very short and blunt; usually 
covered by skin, about 4 length of pectoral spine. 
52. A. nigricans (Le Sueur). GreaAT CaArT-FisH. MIssISsIPPI 
Cat. FLANNEL-MOUTHED Cat. Slaty bluish, growing darker 
with age; body stouter than in the Channel Cat, the head broader, 
lower, and more depressed, the mouth wider, the caudal less forked, 
the skin thicker, hiding the bones of the head; head depressed 
above; supraoccipital above almost reaching second interspinal, 
the bony bridge broken for a short distance only; anal about as 
long as head ; head 4 in length; depth 5; D. I. 5 or 6; A. 25 to 
