30. CATOSTOMIDiE ERIMYZON. 
133 
somewhat inferior ; the upper lii> well developed, freely protractile ; the 
lower moderate, infolded, /y-shaped in outline, plicate, with 12-20 plicm 
on each side. Lowerjaw without cartila^’inoas sheath, rather stronger 
than usual, and oblique in position when the mouth is closed, thus simi- 
lar to the mouth of Ictiobus. Eye moderate, rather high up, placed 
about midway of the head. Suborbital bones considerably developed, 
not very much narrower than the fleshy portion of the check below 
them ; the posterior suborbital concavo-convex, about twice as long as 
deep, sometimes divided ; the anterior somewhat deeper than long, some- 
times divided into two, sometimes united with the preorbital bone, which 
is well developed, and much longer than broad. Opercular bones mod- 
erately developed, scarcely or not rugose. Fontanelle rather large. 
Gill-rakers rather long. Isthmus moderate. Pharyngeal bones weak; 
the teeth quite small, slender, and weak, rapidly diminishing in 
length upwards, each tooth narrowly compressed, with a cusp on the 
inner margin of the cutting surface, and some inequalities besides. 
Scales rather large, more or less crowded forwards, sometimes showing 
irregularities of arrangement ; the longitudinal radiating furrows much 
stronger than usual ; the scales rather longer than deep, but so imbri- 
cated in the adult that the exi)osed surfaces appear deeper than long. 
Lateral line entirely wanting. Scales in the longitudinal series from 
head to base of caudal 35-45 in number ; scales in transverse row from 
base of ventral to dorsal 12-18. Dorsal tin rather short and high, with 
10-11 developed rays, the number usually 11 or 12. Beginning of dor- 
sal flu rather nearer snout than base of caudal. Pectoral tins mod- 
erate, not reaching ventrals ; the latter not to vent. Ventrals under 
a point rather in advance of the middle of dorsal ; their rays normally 
1), but occasionally 8 or 10. Anal fin high and short, more or less 
emargiuate or bilobed in adult males. Caudal flu moderately forked 
or merely lunate, its two lobes about equal. Air-bladder with two 
chambers. Two species known, {ipc, an intensive particle ; to 
suck.) 
1-19. E. SMCClla. (Lac.) Jordan . — Creek Fish ; Cluib Sucker. 
Body oblong, compressed, l)ecoming gibbous with age, the ante-dorsal 
region more or less elevated in the adults, the depth 3)^ in length, ranging 
from 2^ in adults to 1 in young. Dead stout, short, about 4:|: in length 
(1-1^), the interorbital space wide and depressed, the lower parts nar- 
rower. Eye not large, l^ in head (lJ-51). Mouth protractile downwards 
and forwards, the mandible oblique. Scales usually closely imbricated 
