1883.] NATURAL SCIENCES OF PHILADELPHIA. 19 



Cnemidophorus tessellatus Say. Abundant. 



Bascanium pp. Young. 



Crotalus confluentus lucifer B. .and G. Cope emend, supra, p. 11. 



Two specimens from Buffalo Canyon, north of Pyramid Lake. 

 In one of the specimens the dorsal spots are first darker, then 

 lighter-bordered, and there are twenty-three rows of scales on the 

 body. In the other there are twenty-five rows of scales, and the 

 spots have neithfr dark nor pale borders, but have pale scales 

 scattered through them, and they have a more transverse form. 



10. The Lakes of South and West Central Oregon. 



This region possesses mucli zoological intei^est from the position 

 which it occupies as the border-land between the faunae of the 

 Pacific slope and that of the great interior basin. It is here that 

 we find the transition between the sage-brush (Artemisia) desert 

 and the forest-covered Sierra Nevada Mountains and valleys. 

 Here also we have the transition between the almost fresh lakes 

 near the mountains, to the intensely alkaline ones east of them. 

 An especial interest attaches to the lake faunae ; since we find in 

 them the means of determining the characters of the fossils found 

 in the remains of pliocene and post-pliocene lakes of the Oregon 

 desert. This part of the subject will be more fully considered in 

 an essay on the fishes of these lakes, now in course of preparation. 



The routes on which the species of the list below given, were 

 collected, ,are as follows : Along the east shore of the Great 

 Klamath Lake to its northern extremity. From the eastern side 

 of the lake northeastward to Silver Lake. This was part of my 

 expedition of 1879. In 1882, I passed along the three southern 

 Warner^Lakes, and then crossed southwest to Goose Lake. Thence 

 I traveled north to Summer Lake, crossing the Chewaucan River, 

 which flows into Abert's Lake. Then north to Silver Lake, con- 

 necting with my route of 1879, After that, south to Goose Lake, 

 passing along its entire eastern shore. 



Bufo columbiensis Bd. and Gird. 



Abundant throughout the entire region. It is especially numer- 

 ous at Klamath Lake, where it covers the basaltic blocks which 

 lie partially in the water, concealed by the Typhse, which grow 

 from the bottom. They accumulate there in large piles, sometimes 

 as large as a bushel-measure, and afford abundant food for the 

 UiUaenise, which are scarcely less abundant. One specimen of 



