212 bulletin: museum of comparative zoology. 



II. Mammalia. By Outram Bangs. 



During his stay of nearly a month, Mr. Brown set traps for the smaller 

 mammals, at every sort of place on the Savanna of Panama and the 

 edge of the mangrove swamps, but caught nothing, and he saw no signs 

 of small mammals. When I stated this fact to Mr. E. W. Nelson, he 

 said that his experience in Mexico had been much the same, and that 

 such regions in middle America — low, hot, arid plains — are almost 

 without mammalian life. 



One vesper rat (Oryzomys panamensis Thomas ; type locality, near 

 city of Panama), however, has been described from this region. 



Mr. Brown secured specimens of four species of mammals, — one 

 squirrel and three bats. 



SCIURIDAE. 

 1. Sciurus adolphei dorsalis (Gkat). 



Five adult specimens, both sexes, May 20 to 25. 



These are all practically alike in color, except that in some the black is 

 faded, usually in patches, by long wear, to a rusty brown. They are in the 

 " Grizzled-backed phase " of Xelson, with head and back mixed black and 

 yellowish ; under parts pale buff ; tail buff, below along middle, black above 

 and on sides, each hair tipped with white. I cannot see that they differ from 

 Costa Rican examples in the same phase of coloring. It is rather interest- 

 ing that they do not, as north of Panama in Chiriqui and at Punta Burica, 

 Costa Rica, the permanently black form — Sciurus melania (Gray) — occurs, 

 which would thus appear to be merely a colony of melanistic individuals, and 

 hardly a species (or subspecies) in the true sense of the term. 



The flesh measurements are : 



