AMERICAN FROGS OF THE GENUS RANA. 437 



length of head and body 2^ or less than 3 times; males with external 

 vesicles; muzzle more acuminate; no cross-bars on tibia, spots smaller. 

 — Minnesota, Indiana, Georgia, Florida, Louisiana, the types being 

 from Georgia and Florida. 



b. aiistricola, Cope. Head entering length of head and body 2^ 

 to nearly 3 times; no external vocal vesicles; muzzle more or less 

 acuminate; spots less distinct; tibia generally cross-barred; no 

 longitudinal band in front of femur. — The common Mexican form. 



c. virescens, Kalm {utricnlaria, Harl.). Head acuminate but 

 shorter, entering the length 3 times; males with external vocal 

 vesicles; spots smaller, not so distinctly yellow bordered; cross-bars 

 of tibia generally interrupted; a longitudinal band on the front of the 

 thigh. — Eastern and southern coasts from Maine to the mouth of 

 the Rio Grande, and up the Mississippi to southern Illinois, and the 

 intermediate country. 



d. hrachjcephala, Cope. Head shorter and more obtuse, entering 

 the length 3^ times; males without or with rudimental external vocal 

 vesicles; dorsal spots larger, widely yellow bordered; tibial cross- 

 bands complete; no longitudinal band on the front of the thigh. — 

 The common and only form fomid between the eastern part of the 

 Great Plains and the Sierra Nevada Mountains, from Lake Superior 

 and the state of Washmgton to Arizona, Texas, and the Plateau of 

 Mexico; also Quebec, Canada. 



IVIuch as I should have wished to fall in with the arrangement pro- 

 posed by so experienced a herpetologist, who had access to a very large 

 material, although I am afraid he did not make full use of it, I have 

 been unable to follow, and Miss Dickerson observes that living 

 material from New England, New York, Michigan, Minnesota, 

 Wisconsin, Colorado, Texas, and Arizona has not enabled her to make 

 a distinction between the forms mrescens and brachycephala, although 

 she raises R. sphenocephala to specific rank. 



In the specimens examined by me, the proportion of the head to the 

 body does not give very satisfactory results, and the results, such as 

 they are, do not agree with Cope's geographical scheme. In specimens 

 from Ontario and the New England states, the head is 30 to 35 per 

 cent, of the length from snout to vent; in those from Western Canada, 

 .Illinois, Michigan, Idaho, Indiana, Colorado, and Arizona, it is 

 30 to 36 per cent. ; and in those from Florida, Mississippi, and Texas, 

 32 to 37 per cent.'''; while it is 30 to 40 per cent., usually 33 to 38 

 per cent, in those from Mexico and Central x\merica. I should have 



7 29 in one specimen from Texas (No. 48 of table). 



