BLACK-HORSE STICKER. 815 



Diagnosis.— ThiB species may be known by the small head and long 

 dorsal. 



Habits. — It is not rare in the Ohio River, but it seldom ascends the 

 smaller streams. At the Falls of the Ohio it is frequently but irregularly 

 taken, and is sold under the name of Gourd-seed Sucker. It is also called 

 Missouri Sucker and Black Horse. According to Dr. Kirtland, " it 

 migrates down the river at the approach of winter. It is esteemed more 

 highly for food than any other of the family." 



Genus 19. CA.TOSTOMUS. LeSnfiur. 



Catostomus, LeSubur, Journ. Acad. Nat. Scl. Phila., i, 1817, 89 

 Sypentelium, Eafinesqub, Journ. Acad. Nat. ^ci. Phila., i, 1818, 421. 

 Decactylus, Rafinesque, Ichthyologia Obiensis, 1820, 

 Hylomyzon, Agassiz, Am. Journ. Soi. Arts, 1855, 205. 

 Minomus, Girard, Proc. Acad. Nat. Scl. Phila., 1856, 173. 

 Acomvs, Girard, Proc Acad. Nat. Soi. Phila., 1856, 173. 



Type, Cyprinus catostomus, Forstbr = Catostomvs longirostrum, LeSueur. 



Etymology, hato, low; stoma, mouth. 



Head more or less eloBgate, its leugth raogiDg from three and a half to five in body, 

 its form varying considerably in the diiferent subgenera; eyes rather small, high up, 

 median or more or less posterior in position ; suborbital bones narrow, longer than broad, 

 much as in Mytxostoma ; fontanelle always present, usually widely open, in two species 

 reduced to a narrow slit, but never wholly obliterated ; mouth rather large, always in- 

 ferior, and sometimes notably so ; the upper lip thick, protractile, papillose ; the lower 

 lip greatly developed, with a broad free margin, deeply incised behind, so that it forms 

 two lobes, which are often more or legs separated ; mandible horizontal, short, not one- 

 third the length of the head and not reaching to opposite the eye ; lower jaw usually 

 without distinct cartilaginous sheath; opercular apparatus moderately developed, nob 

 rugose ; pharyngeal bones moderately strong, the teeth shortish, vertically compressed, 

 rapidly diminishing in size upwards, the upper surface of the teeth nearly evea, or some- 

 what cuspidate ; body oblong or elongate, more or less fusiform, subterete, more or less 

 compressed ; scales comparatively small, typically much smaller and crowded anteriorly, 

 the number in the lateral line ranging from about 50 to 115, the number in a transverse 

 series between dorsal and ventrals from 15 to 40 ; lateral hue well developed, straight- 

 ish, somewhat decurved anteriorly ; fins variously developed ; dorsal with its first ray 

 nearly midway of the body, with from nine to fourteen developed rays; anal fin short 

 and high, with probably always seven developed rays ; ventrals inserted under the mid- 

 dle or posterior part of the dorsal, typically with ten rays, in one subgenus usually nine, 

 the number often subject to variation of one ; caudal fin usually deeply forked, the 

 lobes nearly equal ; sexual peculiarities not much marked, the fins higher in the male 

 and the anal somewhat swollen and tnberculate in the spring ; breeding males in some 

 species with a rosy or orarge lateral band; air-bladder with two chambers; vertebrae 

 in C. teres and C. nigricans 45 to 47. 



" The slceUion in Catostomus is distinguished by the comparative want of solidity, cer- 

 bones consisting merely of a network of osseous matter. There is a large and broad fon- 

 tanelle on the upper surface of the head, separating the parietal bones, and leading 



