52 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
In numerous specimens examined the head is a little shorter than indicated by 
Dr. Gill’s description, it being 3£ instead of 3 in body to base of caudal. There are 
also other slight differences; the dorsal is VI or VII-17 or IS, and the anal 12 or 13. 
The length of the head is just about equal to its width measured at the preopercular 
spines; the pectoral fins If in head, the rays extending markedly beyond the inter- 
radial membrane. In most specimens the black spots are evident, but some seem to be 
almost or entirely without them ; a dark blotch at base of caudal, and three or four on 
the side are very plain in some indi viduals. One of the specimens, 2j ; inches long, 
from Rattlesnake Greek, is greatly distended with nearly ripe eggs, which gives us 
some idea as to their time of spawning in that region. Some of the specimens from 
this place, and others from the outlet of Swan Lake, have the visceral cavity completely 
rilled by a parasitic worm more than an inch in length, in blobs that are not over 2 
inches long. Some of these parasites were sent for identification to Prof. Linton, who 
says: 
The parasite in the abdominal cavity of the fish is Schistocephalus tiimorphus Creflin. It is im- 
mature. Like Dibotlirium, cordiceps Leidy, of the trout, it attains the adult stage in the intestine of 
fish-eating birds. This, so far as I know, is the first find of this worm in America. In Europe it has 
been found most commonly in Gasterosteus. 
16. Lota lota maculosa (Le Sueur). (PI. xxiv.) 
Gatins maculosus Le Sueur, Jour. Acad. Nat. Sci. Phila., I, 83, 1817. 
A single specimen of the ling was taken in the Red Rock River, and it is said by 
Mr. Scott, of Red Rock, to be common in Red Rock Lake, in which the river has its 
origin. While this is a very widely distributed fish, it has not been previously 
reported from any point near the headwaters of the Missouri. Head, 44; depth, 64; 
eye, 64; snout, 4. The maxillary reaches the posterior edge of the pupil; the barbel 
is a little longer than the eye; pectorals If in head, and about equal to the ventrals. 
Specimens of the following species, introduced into the waters of the Yellowstone 
National Park by the U. S. Fish Commission in 1889 and 1890, were taken and are now 
in the collection : 
17. Salmo irideus Ayres. Rain bow trout. (PL xxiii.) 
Two specimens from Gibbon River above Gibbon Falls. 
18. Salmo trutta levenensis Walker. Loch Leven trout. (PI. xxiv.) 
One specimen from mouth of Heron Creek, Shoshone Lake. 
19. Salmo fario Will. Von Behr trout; Brown trout. (PI. xxiii.) 
One yearling specimen from Firehole River, above Old Faithful Geyser. 
20. Salvelinus fon tinalis Mitch ill. Eastern brook trout. (PI. XXV.) 
One specimen 12 inches long from Indian Creek, near its mouth. 
