GREAT FOKK-TAILED CAT. 789 



the pectorals and ventrals, higher than long, with a pungent spinous ray dentate behind, 

 and about six branched rays ; adipose fin short, inserted over the posterior half of the 

 anal ; anal fin of moderate length, with from fifteen to twenty-six rays, the usual num- 

 ber being tweuty or twenty-one ; caudal fiu short, usually truncate when spread open, 

 slightly emarginate when not expanded, — in species related to Ichihcelurus more or less 

 deeply forked, in some other species rounded ; when the caudal fin is forked the lobes 

 are usually unequal ; ventrals each with one simple and seven branched rays ; pectoral 

 fins each with a stout spine, which is commonly retrorse-serrate behind, these serraevary 

 much with age and circumstances, and do not appear in this genus to furnish good spe- 

 cific characters ; lateral line usually incomplete. 



This genus includes our common Eastern American Catfishes, and is readily recognized 

 by the broad head covered by a thick skin, the free termination of the posterior process 

 of the supraoooipital bone, the compressed body, and by the free adipose fin. ,■'' 



This genus, although undoubtedly a very natural one, is rather hard to definy Cer- 

 tain species (Jmjjus, niveiventris, nigrioans) have real affinities with the species of Ich- 

 thwlurua, having, like them, the body elongate, the head rather narrow, the anal long, , 

 the caudal forked, and the coloration pale. The absence of the connection between 

 the supraoccipital and the interspinal is the only technical character by which Amiurus 

 may be distinguished from Ichthcelurus. 



Analysis or Species of Amiubus. 



* Caudal fin forked NIGRICANS. ,15. 



** Caudal fin rounded, or slightly emarginate. 



a. Anal rays 34 to 36 natalis. 16. 



aa. Anal rays 18 to 22. 



6. Lower jaw longer than upper vulgaris. 17. 



lb. Lower jaw not longer than upper. 

 0. Coloration mottled or variegated; adipose fin large. . maemoeatus. 18. 

 CO, Coloration nearly plain. 



d. Head moderately broad, with a nearly even slope from the tip of the 

 snout to the elevated base of the dorsal fin. 



e. Body elongate ; anal rays 20 to 22 catus. 19. 



ee. Body short and deep; anal rays 18 to 20 melas. 20. 



dd. Head very broad ; an angle at occiput ; anal small, usually with 19 rays. 



XANTHOCEPHALUS. 21. 



15. Amiueus NIGRICANS (LeSueur) Gill. 



Oreat Fork-tailed Cat ; mississippi Cat; Florida Cat; 

 Oreat Catfish of the JLakes. 



Pimelodiis nigricans, LbSueur (1819), Memoires du Museum d'Hist. Nat., v, 153. — Gov. 

 and Val. (1840), xv, 133.— DeKay (1842), Fishes N. Y,, 180.— Storer (1846), 

 Synopsis, 403.—" Hyrtl (1859), Denksohrift Akad. Wiss. Wien, xvi, 16. " 



Amiurus nigricans, Gill (1862), Proo. Best. Soc. Nat. Hist., 44. — .Jordan (1876), Man. 

 Vert. 318.— Jordan and Copeland (1876), Check List, 159 (not of Qunthbr (1864), 

 nor of Cope (1870), equal to A. ccenositB).— Jordan (1877), Bull. U. S. Nat. Mus., x, 83; 

 (1878), Man. Vert., sec. ed., 329. 



Silurus {Pimelodiis) nigrescens, Eichakdson (1836), Fauna Bor.-Am , Fishes, 134. 



Pimelodua sp. incog., Thompson, (1842), History Vermont, 139. 



