Lil 
CATOSTOMIDA. — XXV. 43 
without the characters of the rudimentary subopercle and maxil- 
lary, and the absence of scales, which distinguish the Cat-fishes. 
The chief families are the Cyprinide and the Characinide ; the 
latter, abundant in South America, have an adipose fin and usually 
teeth in the jaws. (ev, well; évrés, within; yvdOos, jaw.) 
Famity XXV. CATOSTOMIDA. (THE Suckers.) 
Body oblong, covered with cycloid scales; head naked ; jaws 
toothless and without barbels, the maxillary forming a large part 
of the edge of the upper jaw; mouth usually protractile, the lips 
generally thick and fleshy ; lower pharyngeal bones falciform, with 
many comb-like teeth in one row; branchiostegals 3; gill mem- 
branes united to isthmus; dorsal fin rather long, of 11 to 50 rays,} 
without spine; anal short; caudal forked; ventrals abdominal, of 
about 10 rays; pectorals low; no adipose fin. Alimentary canal 
long, without ceca. Air-bladder large, divided into two or three 
parts by transverse constrictions. Genera 11, species about 60, 
inhabiting the rivers of North America; two species in Asia. 
The Suckers feed on plants and small amimals; the flesh is rather 
tasteless and full of small bones. They ascend the rivers to spawn 
in spring, at which time the males have usually the A. and C., and 
often other parts of the body, covered with tubercles. 
a. Dorsal fin elongate, its rays 25 to 50 in number; air-bladder in two parts. 
b. Fontanelle present; body oblong-ovate. (Jcttobine.) 
c. Dorsal rays 25 to 35; scales large (34to 41) . . . . IcrioBus, 41. 
bb. Fontanelle obliterated by the union of the parietal bones; body elon- 
gate. ( Cycleptine.) 
d. Mouth small, inferior, with thick papillose lips; scales small (56). 
CYCLEPTUS, 42. 
aa. Dorsal fin short, its rays 16 to 18. (Catostomine.) 
e. Air-bladder in two parts; lower pharyngeals slender, with small teeth. 
jf. Lips thick, papillose; lateral line complete and continuous; scales 
small (55 to 115); fontanelle present; mouth small, inferior. 
CaTostomus, 43. 
Ff. Lips thin, plicate; scales large (40 to 50). 
g. Lateral line wholly wanting, at allages. . . . Ertmyzon, 44. 
gg- Lateral line imperfect in young, nearly complete in the adult. 
MINYTREMA, 45. 
ee. Air-bladder in three parts; fontanelle present; scales large (about 
45); lateral line complete. 
h. Mouth normal, the upper jaw protractile; the lips more or less 
plicate. 
i. Lower pharyngeal bones moderate, the teeth compressed, gradu- 
ally increasing in size downward. . . . - MoxostToma, 46. 
zi. Lower pharyngeal bones very strong, with the lower teeth much 
enlarged, subcylindrical and truncate; the upper teeth small 
and compressed. . . + + « + «+ + PLACOPHARYNX, 47. 
1 In this family, the rudimentary rays before dorsal and anal are not counted. 
