360 
ZOOLOGY. 
pupil. Insertion of the ventral fins opposite the seventh ray of the dorsal. Caudal posteriorly concave. Dorsal fin ante- 
riorly concave. Lower fins moderately developed. Scales deeper than long, grooved on all sides. Reddish brown above ; 
silvery beneath. 
SYN.—Oarpiodes damalis, Grt>. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 170. — Ibid. Gen. Rep. Fishes, 218. 
A large number of these fish were obtained from sunken pools on Milk river, Nebraska. 
When properly cooked they are not unpalatable. 
ACOMUS LACTARIUS, Grd. 
nillk River Sucker. 
Plate L. 
Sp. Ch. — Head constituting somewhat less than the fifth of the total length. Mouth small ; lips well developed, covered 
with uniform granules. Eye large, sub-circular ; its diameter entering five times in the length of the side of the head. 
Anterior margin of dorsal fin somewhat nearer the insertion of the' caudal than the extremity of the snout. Insertion of 
ventrals situated opposite the posterior half of the dorsal ; their tip extending to the vent. Grayish brown above ; grayish 
white beneath. 
Syn. — Catostomiis (Acomus) lactarius, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 174. 
Acomtu lactarius, Grd. Gen. Rep. Fishes, 223. 
This sucker was obtained by me in the lagoons along the course of the upper part of Milk 
river, Nebraska. At the season of the year in which I visited that locality, the bed of the 
river being dry in many places, these fish, with others, had retreated to deep holes and small 
stagnant lagoons in great numbers. With a small seine I was enabled to take, in a very brief 
space of time, many valuable ichthyological specimens, consisting of individuals of the present 
species, besides other cyprinoids, pike, perch, &c., some of which were carefully preserved for 
the national collection, and others afforded a welcome addition to our usual monotonous fare. 
CATOSTOMUS SUCKLII, Grd. 
JVebrasIia Sucker. 
Plate LI. 
Sp. Ch. — Head constituting the fifth of the entire length. Eye small. Mouth rather small ; lips moderately developed, 
covered with conspicuous papillfe. Isthmus of medium width. Dorsal fin as higli as long ; its anterior margin somewhat 
nearer the insertion of the caudal fin than the extremity of the snout. Insertion of ventrals a little in advance of the 
middle of the dorsal, and equidistant between the extremity of the snout and the fork of the caudal. Posterior extremity 
of anal extending beyond the rudimentary rays of the caudal. Grayish olive above ; yellowish olive beneath. 
Syn.— CatoitomMs sucklii, Grd. in Proc. Acad. Nat. Sc. Philad. VIO, 1856, 175. — Ibid. Gen. Rep. Fishes, 226. * 
The present fish is not uncommon in the upper Missouri and its tributaries, in the same 
localities as the last mentioned species. 
In 1854 I noticed in one of the branches of Snake river, Oregon, a sucker of about the same 
size and of much the same general appearance as this. Its colors on the back, however, were 
darker. Owing to a deficiency in the means of transportation, and to other causes, I was unable 
to preserve this fish, which I regret the more because it was the only specimen of a genuine 
sucker (catostomus) that I saw west of the Eocky mountains. 
PIMEPHALES FASCIATUS Grd. 
Sp. Ch. — Body anteriorly stoutish, its depth being contained five times in the total length, in which the head enters four 
times and a half. Eye moderate and circular, its diameter being contained somewhat more than four times in the length of 
