AMERICAN FROGS OF THE GENUS RAN A. 451 



description. However, according to Camp, specimens from Men- 

 docino City, Coast of California, "are intergrades between aurora and 

 (hai/tonii" and he accordingly regards the latter as a subspecies of the 

 former; but he does not state in what respects they intergrade. I 

 therefore provisionally maintain the two as species. 



I regard R. aurora as intermediate between R. draytonii and R. 

 pretiosa, but nearer the former. Until I was able to examine authen- 

 tic specimens of this frog, which has unaccountably been referred as a 

 subspecies to the European R. agilis, I felt somewhat doubtful as to 

 the validity of this species. 



The description of Baird and Girard and of Cope do not afford 

 con\'incing characters for the separation from R. draytoni, and Miss 

 Dickerson makes the following statement : — 



"Rami aurora is easily confused with R. draytonii, because of the 

 likeness, both in coloring and proportions. The former frog can be 

 distinguished by the following characteristics: It has a longer leg, 

 the greater length especially noticeable in the tibia. ^ Its skin is very 

 smooth, while that of R. draytonii, especially in the full-grown frogs 

 is always tubercular,^ and may be extremely so (even on the ear). 

 R. aurora has a longer foot with a broader web, but with a much 

 smaller inner sole tubercle. "^^ It is said not to exceed 90 millimeters 

 from snout to vent. 



Cope says the two last phalanges of the fourth toe are free from the 

 web in R. aurora, instead of only the last in R. draytonii, but the 

 figures in his book show absolute identity between the two species in 

 this respect. He adds that the tongue is "small and narrow" in the 

 former and "not large" in the latter, but the tongue is decidedly 

 small and narrow in our specimens from Riverside, remarkably so in 

 the male,^^ which I cannot otherwise distinguish from R. draytonii. 



According to Cope's measurements (in percentages) the differences 

 in the proportions between the two species are: — 



8 Tibio-tarsal articulation reaching beyond end of snout; tibia much longer 

 than femur. — Meek, probably guided by Cope's description, refers to this 

 species a specimen in which the heel only reaches the center of the eye. 



9 Some of my largest R. draytonii have the upper parts smooth. 



10 This statement is interesting in connection with Stejneger's comments on 

 my suggestion that R. boylii might be a variety of R. draytoni. 



11 One third the length of the inner toe, according to Miss Dickerson's figure. 



12 I also find a remarkably small tongue in some males of R. japonica from 

 Satsuma, and of R. temporaria from the Alps. 



