AMERICAN FROGS OF THE GENUS RANA. 429 



Measurements of Females, in Millimeters. 



From snout to vent 70 68 



Head 22 23 



Width of head 27 23 



Snout 7 7 



Eye 7 7 



Interorbital width 3 3 



Tympanum 7 6 



Fore limb 38 34 



1st finger 8 8 



2nd " 7 7 



3rd " 9 9 



4th " 6 6 



Hind limb 94 100 



Tibia 30 31 



Foot 31 33 



3rd toe 18 21 



4th " 27 30 



5th " 19 21 



Habitat. — Utah and Nevada. 



This species is here described from three specimens, two females and 

 one yomig, from Las Vegas, Nevada, for which I am indebted to the 

 kindness of Dr. Stejneger and Miss Dickerson. 



The affinity is very close to R. clamitans, the only character which 

 may serve to distinguish R. onca being the somewhat greater pos- 

 terior extension of the dorso-lateral fold. It is difficult to conceive 

 the reasons which have induced Cope to place this frog as a subspecies 

 of R. draytoni. 



Miss Dickerson says the tympanum is larger in males than in 

 females, and that the body is often bright green in front and brown 

 behind, characters in which it approaches R. clamitans, whilst the 

 spotting reminds one of R. halecma. 



6. Rana virgatipes. 



Rana virgatipes Cope, Amer. Nat. XXV, 1891, p. 1017; W. J. Davis, Amer. 

 Nat. XXXVIII, 1904, p. 893, and XXXIX, 1905, p. 795; Fowler, Proc. Ac. 

 Philad., LVII, 1905, p. 662, PI. xl; Dickerson, Frog Book, p. 222, PI. xiii, 

 and PI. Lxxxiv, figs. 4, 5 (1906); Fowler, Rep. N. Jers. State Mus. 1907, p. 

 194; BoxjLENG., Ann. and Mag. N. H. (9) III, 1919, p. 409. 



