138 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



reiidciing it uiivsightly. Speciiucus collected by Dr. Jordan tlie previous 

 year had l)cen examined l)y hini, but observations were desired ou 

 fresh material and in relation to the lite history of the sj^ecies. 



The party reached the park about the middle of July, and, provided 

 with a very comi^letc outfit, began at once their examinations, which 

 were continued until August 30. The ground gone over was prac- 

 tically the same that had been traversed by Dr. Jordan in 1889, in- 

 cluding the Gardiner, Madison, and Yellowstone river systems ou the 

 Atlantic slope of the continental divide, and that of the Snake River ou 

 the Pacific slope. Collections were made in 43 localities. The priuci- 

 l)al Ashless waters visited were Shoshone and Lewis lakes, the upper 

 Gibbon and its tributaries, the Firehole and its l)ranches, (Joose Lake, 

 Twin Lakes, Swan Lake, and Tower Creek. The effects of geyser and 

 hot-spring overflow were studied especially on tlie Firehole and on Alum 

 Creek, and of the intervention of falls ou the Gibbon Eiver and some 

 of its tributaries. The highest waters examined were Mary Lake, 

 having an altitude of 8,200 feet, and a small lake, near Norris Pass, at 

 about the same level. Dredging was carried ou in Yellowstone Lake 

 to a dei)th of 195 feet. The general collection of specimens obtained is 

 very large, and lias been sent to the State Laboratory of Natural His- 

 tory, at Champaign, 111., where it is being carefully studied under the 

 direction of Prof. Forbes. It is considered to be suflicientlj'" complete 

 to explain the biological conditions existing in those lakes, ponds, riv- 

 ers, and creeks which are devoid of fishes, in such as have only a single 

 species offish, and again in others supporting from 3 to 8 species each. 

 Awaiting the preparation of Prof. Forbes's report, we are able, in this 

 connection, to jn^esent only a few of his preliminary conclusious, which 

 are as follows : 



The waters of the park, wherever they were examined, were found to 

 provide a fair amount, and often an abundance, of animal life suitable 

 as food for the ordinary carnivorous fishes, the Ashless areas being no 

 less well supplied in this respect than those already containing trout. 

 These observations, therefore, support those of the ichthyologists, that 

 the peculiar distribution of the fishes in this region can be explained 

 alone from its topographical features, which have had no noticeable 

 effect upon the distribution of invertebrates. Collections made both 

 above and below thel'alls in certain rivers show that these obstructions 

 to llsh migrations have in no way interfered with the dissemination of 

 the lower forms. The scarcity of fresh-water mussels and crayfishes 

 is probably due to the chemical condition of the waters, esi)ecially in 

 the absence of lime. The former were found only in Canon Cree*k, 

 where the living specimens were greatly eroded and the dead shells 

 rapidly decalcificid. Crayiishes have also been recorded from only a 

 single stream. No isopod crustaceans were discovered, and aiui)hipods 

 were very irregularly distributed, being very abundant in some jdaces 

 and entirely wanting in others. No phyllopod crustaceans were col- 



