FISHES. 



117 



and smooth, the mouth rather large, with thin lijjs and eight barbels, the palate tooth- 

 less, the gill membranes free from the isthmus, the adij)ose fin short, the dorsal fin 

 shoi-t, armed like the pectoral with a sharp spine, and the anal fin of moderate length. 

 Twenty-five species are well known, and these are usually placed in five genera, 

 •although two of these ( Gronias and Ainiurus) are very similar to Ictalurus. 



The genus JVbturus is distinguished by the form of its adipose fin, which is long 

 and low, adnate to the back, and joined to the caudal. Its species, eight or nine in 

 number, are known as stone-cats, and are very small in size, most of them not exceed- 

 ing six inches in length. They abound in small brooks, among logs and weeds, in the 

 southern and western states. The wounds produced from the sting of their sharp 

 pectoral spines are excessively jjainful, in character much like those caused by the 

 sting of the dorsal spines of Scorpcena, and much more severe than an ordinary bee- 

 sting. In the axil of the pectoral is a pore, which is probably the opening of the duct 

 of a poison gland. " From it," observes Professor Cope, who was the first to notice 

 this character of Noturus, " may fi-equently be drawn a solid gelatinous style ending 

 in a tripod, each limb of which is dichotomously divided into short branches of regular 



— Amiurus nebulosus, hox'ned-pout, bull-head. 



length." Nothing further is known of this poison gland, a feature which is well worth 

 a thorough study. 



The genus Xeptops contains a single species of large size, the mud-cat {Leptops 

 olivaris), living in muddy bottoms of sluggish streams and lakes throughout the 

 west and south. It has a large flattened head and projecting lower jaw, and is 

 especially distinguished from the species of Amiurus by the arrangement of its teeth. 



The genus Gronias comprises a single species {G. nigrildbris), a small blind cat- 

 fish, a few specimens of which have, been taken in a cave in southeastern Pennsyl- 

 vania. It differs from Amiurus only in the partial obsolescence of its eyes, and it is 

 doubtless a recent oiSshoot from some of the eyed species found in that region. 



The genus Amiurus comprises most of the common cat-fishes, fifteen species being 

 at present recognized. Of these, the best known and most abundant species is Amiu- 

 rus nebulosus, the common horned-pout or bull-head of New England, the small cat- 

 fish of the great lakes, and generally distributed in the ponds and bayous of the 

 north and east. Lately it has been introduced into the waters of California, where it 

 has thrived remarkably, and already it is one of the most important food-fishes of the 

 Sacramento basin. It is an especial favorite with the Chinese at San Francisco. 



