EXPLORATIONS IN YELLOWSTONE NATIONAL PARK. 
47 
Compared with the young of G. catostomus (from Keweenaw Bay), C. grisetis has 
the upper lip much thicker, with 5 or 6 instead of about 3 rows of tubercles. The 
lower lip is' much larger in C. griseus, and the lower Jaw has a rather distinct cutting 
edge. The head is larger, and the eye larger in griseus, and the scales ou the pos- 
terior part of the body are less reduced in size. I am uot sure, however, of the per- 
manent value of any of these characters. The specimens from Gardiner Eiver have 
the scales 88 to 90, while in more typical examples of G. griseus (from the South Phitte 
River at Hartsell’s Hot Springs and at Denver) the scales are 105 to 110. Should 
the difference prove constant, the specimens from the Upper Missouri region should 
stand as a separate variety of Gatostomus griseus lactarius. It is not at all likely that 
these characters can be depended upon. 
Dorsal rays 10 or 12 ; fontanelle well developed ; color, dark gray, irregularly 
mottled and barred with black. 
2. Catostomus ardens Jordan & Gilbert. (Plate VII, Fig. 2.) 
Head 35. to 4 in length ; deiith, 4J to 4^' ; D. 2.11 to 2.13 ; A 7. Scales 12-70 to 
72-12. Length of types, 6 to 8 inches.* 
Body moderately elongate, not strongly compressed ; head broad, acutely conical, 
the snout short and sharp, 2^ to 2J in head. A depression behind tip of snout, so that 
it forms a distinct projecting nose. Eye small, 5;]- in head. Lower jaw rather strong, ob- 
liquely placed, 2|. in head. Mouth small, the lips full, the upper thick, with about G rows 
of rather coarse papill® ; lower with many rows of papillae which are coarser in front, 
the lip deeply biM : lower jaw without evident cartilaginous sheath. Interorbital 
space broad, 2f i n head. Fontanelle well dev eloped. Scales small, crowded anteriorly, 
about 32 before dorsal. Fins moderate ; dorsal with its free margin nearly straight, 
its longest rays reaching when depressed somewhat beyond the middle of the last 
rays, their length If in head. Caudal moderate, well forked, the upper lobe the longer, 
the peduncle moderate. Pectorals long, 1^ in head. Yentrals and anal moderate. 
Color grayish-olive above, paler below ; no distinct markings ; the young vaguely 
barred with dark olive. Very abundant in the warm waters of Witch Creek,, the 
young also abundant in Heart Lake. The largest taken are about 8 inches in length. 
This species seems to be indistinguishable from the common sucker of Utah, Gatos- 
tomus ardens, aud is quite unlike the Gatostomus macrocheihis of the Lower Columbia. 
This fact, together with the general affinity of the Ashes of Heart Lake with those of 
the Great Basin, suggests that the fauna of the Upper Snake River, above the great 
Shoshone Falls, may have been derived from the Great Basin rather than from the 
Lower Columbia. The effect of the Shoshone Falls as a barrier to the distribution of 
Ashes is worthy of a careful investigation. 
About one specimen iu every three or four of Gatostomus ardens was found to 
contain a long, Aat, intestinal worm of unusual size, so large as much to distend the 
walls of the abdomen. Some of these worms were more than a foot in length, aud 
greater than the whole abdominal viscera of the Ash. The worm is apparently loose 
iu the abdominal cavity, aud can be found iu every case by making an incision along 
the median line of the belly. The infected individuals did uot appear poor or dis- 
* A much larger example, some 16 iuches long, has since been sent ns by Dr. S. A. Forbes. It was 
taken with a trammel net iu Heart Lake in July, 1890. The lips seem a little fuller in the Heart Lake 
fishes as compared with those from Utah. 
