98 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — III 



Early writers on fishes, as well ;is most foi('I<;ri iditliyologists, havi- 

 considered the Suckers as t'onuinf; a niere tiil)e oi' subfamily of the 

 C!fprini(I(r, whi(;h gioup has been variously denoniinated Catostomi, 

 Catastomina, and Cato>»(ominiv, but t!ie characteis above noti'd, of teeth 

 and mouth, seem to the writer to fully jnstily their separation as a dis- 

 tinct family TW' dorsal fin in 0»/o.v^o»j/rfcr is more develojied than i>* 

 nsual in American C^pnnithr, although various Old World genera show 

 similar characters. The development of the lips and the great profrac 

 tility of the mouth aie leatures usually diagnostic, but in the genus 

 Quassi'ahia the mouth is scarcely i)iotractile, and among our Cypri- 

 wjrfrt' certain species of Phenacobiv.s and Ceratielithys hnve thicker lips 

 than have some of the Cato.stomidw. 



The Catofitoondw fall at once into thiee well-marked subfamilies, first 

 indicated by Professor Gill, and termed by him Catostomincr, Cycleptince, 

 and Buhalichthyincc. These may be characteri:;ed as follows: — 



Ca(ostomina\ — Body oblong or elongate, subterete or more or less 

 compressed : dorsal fin nearly median, short and sub(iuadrate, with 

 from nine to eighteen developed ravs: ventral fins under the dorsal, of 

 nine; or ten rays : anal fin high and short, normally of seven rays, nearer 

 the base of the caudal th;in that of the vential fins: lips well developed, 

 usually papillose or plicate: gill-rakers little developed. Genera Quassi- 

 labia, Placopharynx, Myxostoma, Erimyzon, Minytrema, Chasmistes^ 

 Catostomus, Pantostetis. 



Cyckptiiuv. — Body elongate, slender: dorsal fin falciform, of about 30 

 rays, beginning over the interval between the jiectoral and ventral fins, 

 and extending as far back as the beginning of the anal fin : ventral fins 

 10 rayed; anal fm small, of about 7 rays: head extremely small: scales 

 moderate, with the exposed suifaces broad : fontauelle entirely obliler- 



times absent; tlic head is diversi'orni ; the ojjercular bones normally developed ; tbe 

 nostrils double ; the nioutb more or less inferior, and provided with llesby and gener- 

 ally papillose or crenated lips; the upper jaw is formed on tbe middle by the small 

 and lamellifoim interniaxillaries, and on the sides by the supnimaxillaries ; teeth are 

 wanting in the jav^i; the pharyngeal bones are developed in a falciform manner, and 

 provided with a row of numerous conib-like teeth ; the branchial apertures are re- 

 stricted to the sides; brauchiostegal rays three on each side ; dorsal variaVile in devel- 

 opment; anal posterior, and gem-rally t-hort and high; caudal large, and more or less 

 emarginated; pectoral fins low down, but lateral and with their rays branched; ven- 

 tral fins abdominal ; ihi' intestinal canal is very long; the stomach simple and desti- 

 tute of pyloric cieca ; the air-bladder is large, unprotected by an osseous capsule, and 

 divided by transverse coustrictious into two or three regions." 



