SILUEID^. 75 



tion of the supraocsipital or interparietal bone into the head of the 

 second interspinal. A firm and immovable bridge is thus formed, 

 which gives an uninterrupted passage from the dorsal fin to the snout. 

 The silvery coloration is also a marked distinguishing feature. 



It is not generally true that the species of Ichthceljirus reach a 

 larger size than those of the other genera. Amiurus nigricans and Fe- 

 lodiehthys oUvaris far exceed in size any of the species of Ichthcelurus. 



ANALYSIS OF SPECIES.* 



*. Anal fin extremely elongate, its base about one-tbird tbe lengtb of tbe body (without 

 caudal); its rays 32 to 34 in number ; eye small, wholly anterior, the middle of 

 the head being entirely behind its posterior margin; head small, about 4^ in 

 length ; depth 4 in adults to 5^ in younger specimens ; slope from dorsal to snout 

 somewhat concave, especially in adults ; pectoral spine 1^ in head ; skin thin ; 



color brightly silvery Fukcatus, 1. 



**. Anal fin shorter, 3| to 4 in length ; its rays 24 to 30. 



t. Eye moderate-sized, anterior, the middle of the head being wholly behind it ; anal 

 rays 27 to 30 ; body comparatively stout and deep, compressed behind ; the dorsal 

 region elevated ; depth 3i to 4 in length; head pretty large, 4|^ to 4^ in length, 

 one-third longer than broad ; spines moderate, strong, little more than half-head ; 

 profile from dorsal to snout more or less depressed or concave ; skin rather thick ; 

 colors pale Eobustus,2 



tt. Eye large, placed me8ially,the middle of the length of the head falling within 

 the eye ; anal rays 25 to 29 ; head moderate, about 4 in length ; depth about 5 ; 

 body more elongate and less deep than in rohustus, the head rather smaller, the eye 

 larger, and the dorsal region less elevated ; pectoral and dorsal spines long, each 

 about If in length of head Punctatus, 3. 



1. lOHTH^LUEUS FUEOATUS, {Guv. & Val.) Gill. 

 Fork-tailed Channel Cat. 



(Figs. 1 and 2.) 

 Pimelodus fureatus, Cuv. & Val. (1840), sv, 136.— De Kay (1842), Fishes N. Y. 187.— 

 Stouer (1846), Synopsis, 403. 

 Ictalurus fureatus, Gill (1832), Proc. Bost. Soc. Nat. Hist. 43. — Jordam (1876), 



Man. Vert. 300.— Jordan & Copeland (1876), Check List, 159. 

 Amiurus fureatus, Gunther (1864), Cat. Fishes, v, 103. 

 Pimelodus affiuis, Baird & Girard (1854), Proc. Acad. Nat. Sci. Phila. 26. — Girard 

 (1859), Ich. U. S. and Mex. Bound. 32. 

 Ictalurus affiuis, Gill (1862), 1. c. 43. — Jordan & Copeland, 1. c. 159. 

 . ^HUurMS a^«is, GiJNTHER (1865), I.e. 103. 



Habitat. — Mississippi Valley to Texas. 



This species is not nearly so common nor so well known as the 

 punctatus. I am unable to distinguish the type specimens of affinis 

 from fureatus. 



* I. me7-idionaUs is here omitted, the description not being sufficiently full to allow 

 a satisfactory contrast of Hs characters with those of /. rohustus. 



