SILUEID^. 75 



tion of the supraocsipital or interparietal bone into the bead of tbo 

 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 uot generally true that the species of Ichthwl.uriis reach a 

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

 lodichthys olivaris far exceed in size any of the species of Ichthcclurus. 



ANALYSIS OF SPECIES.* 



*. Anal fifl extremely elongate, its base about oue-third the length of the body (without 

 caudal); its rays 32 to 34 in number ; eye small, wholly anterior, tlio 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 H JQ head; skin thin; 



color brightly silvery Fuhcatus, 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 3| 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 Robustcs,2 



tt. Eye large, placed mesially,the middle of the length of the head falling withm 

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

 body more elongate and less deep than in rohmtus, 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 Puxctatus, 3. 



1. ICHTH^LUEUS FUECATUS, [Guv. & Val) Gill. 

 Fork-tailed Channel Cat. 



(Figs. 1 and 2.) 

 Pimelodus fiircatus, Cuv. & Val. (1840), xv, 13G.— De Kay (134i3), Fishes N. Y. 187.— 

 Stoueu (1846), Synopsis, 403. 

 Ictalunis furcatus, Gill (1862), Proc. Bost. Soc. Nat. Hist. 43.— Jordan (1376), 



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

 Amiurus furcatus, Gunthkr (1864), Cat. Fishes, v, 103. 

 Pimelodus affinis, Baikd & Gihakd (1854), Proc. Acad. Nat. Sci. Phila. 26.— Gikard 

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

 Ictalums affinis, Gill (1862), 1. c. 43.— Jordan & Copklaxd, 1. c. 159. 

 Amiurus affinis, Gunthek (1865), I.e. 103. 



^a&itot— 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 furcatus. 



• J. memZtona/is is here omitted, the description not being sufficiently full to allow 

 a satisfactory contrast of 'ts characters with those of /. robusius. 



