412 Mr. G. A. Boulenger on the 
2. Tips of fingers obtuse or rather pointed; vomerine teeth be- 
tween choane; tympanum } to $ diameter of eye; tibio- 
tarsal articulation reaching eye or tip of snout; tibia 1? to 
21 times in length from snout to vent; dorso-lateral fold 
prominent, its distance from its fellow, on the back, 4 to 5% 
times in length from snout to vent; no outer metatarsal 
tubercle; head as long as broad or a little broader than long ; 
male with internal vocal sacs .. R. palmipes, Spix. 
B. Loreal region vertical or nearly so; toes 3 to # webbed; tips of 
fingers swollen; tympanum 3 to 3 diameter of eye; tibio- 
tarsal articulation reaching eye or between eye and tip of 
snout; heels overlapping ; tibia 5 to 6 times as long as broad, 
12 to 2 times in length from snout to vent; dorso-lateral fold 
prominent, its distance from its fellow, on the back, 5 to 6 
times in length from snout to vent; no outer metatarsal 
tubercle ; head as long as broad or a little longer than broad ; 
male without vocal sacs ........ R. ceruleopunctata, Stdr. 
The American frogs all belong to the subgenus Rana, 
agreeing with the type-species, R. temporaria, L., in the 
structure of the pectoral arch (strong horizontal clavicles, 
omosternal style not forked at the base). I conceive the 
most primitive type as with large nasal bones in contact 
with each other and with the frontoparietals entirely cover- 
ing the ethmoid ; pointed, fully webbed toes with the outer 
metatarsals separated by web to the base ; a distinct tym- 
panum; no glandular dorso-lateral fold*. I therefore 
regard the species grouped together in division I. A. of the 
above synopsis as nearest to this prototype ; from this group 
I. B. 1. and II. seem to be directly and independently derived, 
probably also I. B.2.6.; whilst I. B. 2.a. is obviously con- 
nected with J.B.1. The species under Division II. are 
furthest removed from the prototype; I see no reason for 
regarding R. boylit as nearly allied to the Rane temporaria, 
and it is connected with R. palmipes by R. pustulosa. 
1. Rana catesbiana, Shaw, 1802. 
R. hoans (non L.), Lacep., 1788.— R. mugiens, Merr., 1820.—A. scapu- 
laris, pipiens, Harl., 1825,—2R. conspersa, Leconte, 1855. 
North America east of the Rocky Mountains, from Canada 
(Quebec, Ontario) to Florida and Texas. 
2. Rana grylio, Stejneg., 1901. 
Florida, Mississippi, and Louisiana. 
* Cf. Bull. Soc. Zool. France, 1918, p. 111. 
