2. — DESCRIPTION OF A NEW SUCKER, PANTOSTEUS JORDAN!, FROM THE 
UPPER MISSOURI BASIN. 
BY BARTON W. EVERMANN, PH. D., 
Assistant, (J. S. Fish Commission. 
In the following paper is given a description of a new species of sucker, Pantos- 
teus jordani , together with a discussion of the distribution of the various species of 
the genus Pantosteus , it being thought advisable to publish this in advance of the 
completion of a report upon investigations in the Black Hills region upon which I am 
now engaged, and of which this is to be regarded as forming a part. 
PANTOSTEUS JORDANI sp. nov. 
Pantosteus virescens, Jordan, Bull. 4, vol. iv, U. S. Nat. Mus., 1878, 780 (Sweet Grass Hills, Montana). 
Catostomus discobolus, Evermann, Bull. I T . S. Fish Comm. 1891, pi. xviii, fig. 1, 41 (Red Rock River, 
Red Rock, Mont., and Beaverhead River, Dillon, Mont.). 
Head, 4£ to 5£; depth, 4J to 5; eye, 4£ to 5 ; snout, 2 to 2J; interorbital width, 2|-; 
D. i, 10; A. I, 7; scales, about 16-96- 14, 48 before the dorsal. 
Body rather stout, subterete, back gently and regularly arched from snout to ori- 
gin of dorsal, thence nearly straight to base of caudal; head small, short, and conic, 
interorbital space broad and but little convex; snout long, about half length of head; 
mouth large, broad; lower lip broad, very little incised, covered with tubercles of 
moderate size ; upper lip also broad, extending well down on sides of mouth, tubercles 
in about 3 or 4 rows ; cartilaginous sheath of lower lip well developed ; caudal peduncle 
stout, not much compressed; scales small and much crowded anteriorly, lateral line 
straight and near axis of body; dorsal small, its height 1+ in head and a little greater 
than base of fin, its origin considerably nearer snout than base of caudal; pectorals 
long, about equal to length of head, reaching more than half way to the ventrals; 
ventrals short, not reaching vent; anal about + longer than pectorals, reaching base 
of caudal ; fontanelle reduced to a very narrow slit, practically obliterated in the older 
individuals; peritoneum very black ; air-bladder small, the posterior part long and 
very slender. 
Color, dark-greenish above, scales covered very closely down to the paired fins 
with innumerable fine dark or greenish specks, most numerous on back; under parts 
pale; in life, or immediately upon putting in alcohol, some specimens were observed to 
have a broad orange band along the side, this probably being a marking present dur- 
ing the breeding season. Young specimens 2 to 3 inches long are frequently mottled 
very much like the young of Catostomus teres and C. nigricans. 
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