784 FISHES — SILURID^. 



Third superior pharyngeal bone wanting, or small and resting on the fourth, second di- 

 rected backwards ; one or two pairs of basal branchihyals ; subopercnlum wanting; pre- 

 maxillary forming mouth-border above ; interclavicles present." A large order, in some 

 respects intermediate between the Sturgeons and the Cyprihidce. The leading family is 

 the Siluridce, 



* Opercle present ; dorsal fin inserted in front of the ventrals. . . SiLiJKiDiE. 7. 



FAMILY VII. SILURIDiE. THE CAT-FISHES. 



This family includes such of the Nematognathi as have the rayed dorsal fin short, and 

 placed in advance of the ventrals, and the operculum developed. The variation in appear- 

 ance among the members of this family is great, some having the skin naked, others hav- 

 ing it covered with bony plates of various forms. The American fresh water species, some 

 thirty in number, agree in having the body naked ; the head with eight long barbels 

 whereof the maxillary bones form the base of the longegt pair ; no subopercle ; top of 

 head not mailed ; dorsal and pectoral fins each with a pungent spine, which is often 

 serrate; adipose fin present, without rays; gill openings wide. 



There are upwards of seven hundred species of Siluridaa known, referred to about one 

 hundred genera. They are most numerous in the fresh waters of South America, and 

 are numerous enough in North America and Africa. A few occur in Europe, and some 

 are marioe Our species are valued for food in proportion to their size. They mostly 

 inhabit lafees and sluggish streams, and are usually very tenacious of life. 



♦Adipose fin, with its posterior margin free, not adnate to the body, nor connected 

 with the caudal fin. 



14, Band of t«-eth on the premaxiUaries, without lateral backward processes. 

 5 Sapraoccipital bone produced backward from the skull, receiving the pointed 

 anterior end of the second interspinal (bone at the base of the dorsal fin), thus forming 

 a continuous bony bridge from the head to the dorsal ; (slender silvery species, with small 



mouth and forked caudal fin) ICHTHiELURTJS. 10. 



lb. Supraocoipital bone not produced, falling short of the interspinal, the bony 

 bridge being therefore interrupted; (stout dusky-colored species, with larger mouth and 

 less forked or truncate caudal fin. ..... Amiurus. 11. 



aa. Band of teeth on the premaxillary, with a strong backward extension on each 

 side; lower jaw longest; anal fin short. . . . Pblodichthys. 12. 



** Adipose fin low, keel like, adnate to the body, and usually continuous with the 

 caudal fin. ....... . Notukus. 13. 



Genus 10. ICHTH^LURUS. Eafinesqne. 



letalurus, Eatinksquk (1820), Ichthyologia Ohiensis, 61. 

 ElUops, Eafinesqdb (1H20), Ichthyologia Ohiensis, 62. 

 Syneohoglanis, Gill (1859), Annals Lye. Nat. Hist., vii, 39. 

 letalurus, Gill (1862), Proo. Boston Soo. Nat. Hist., 41. 



Ichthcelurns, Cope (1869), Journ. Acad. Nat Sci,, Pbila., 237, (Corrected orthography,) 

 Type, Silurws punctaius, Bafinesque. 

 Etymology, lohihus, fish ; ailotirus, cat. 

 Body elongated, slender, and much compressed. The caudal peduncle is short but 

 slender, and presents behind the anal an elongated elliptical section. 



