1894.] - Zoology. 435 
son species U. scopifera, and give the following differential diagnoses of 
the two. 
Uma norata Baird. Femoral pores 17-18; labial scales nearly 
flat ; fringes of the inferior eyelid longer than those of the superior ; 
occipital plate larger; digits longer, with shorter fringes of spines; 
colors pale. 
Uma scoparta Cope. Femoral pores 30 in one row, with a second 
row of 12; labial scales strongly keeled; fringes of eyelids equal; 
occipital plate smaller; digits shorter, with longer fringes of spines ; 
ground color above black, marked with closely placed discoidal light 
spots with a black center. (No. 6065 U. S. National Museum). 
The fringed digits and sole of this genus constitute an excellent 
example of homoplassy. Similar fringes are present in the same posi- 
tions in the Asiatic Agamid genus Phrynocephalus, and in the African 
Gecconid genus Ptenopus. Both of these, like Uma, are inhabitants 
of deserts. The spines which compose the fringes penetrate the sand, 
and give the animal a better hold on it than is secured by the ordinary 
squamation. 
I give figures of the feet of Ptenopus kd td Smith and Uma scopa- 
ria in illustration of this point.—E. D. Cor 
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Fics. 1-2 Prenopus garrulus ; 1 anterior foot; 2 anterior digit; from Boulenger. 
Fics. 3-4 Uma scoparia ; 3 anterior ; 4 posterior feet. 
