American Species of Rana. 409 
or eye; heels meeting or narrowly sepa- 
rated; tibia 2} to 23 times in length 
from snout to vent; web extending to 
tip of fourth toe ; no dorso-lateral fold. 2, grylio, Stejn. 
Vomerine teeth on a level with posterior 
borders of choanz, or just behind 
them; first and second fingers equal ; 
tibio-tarsal articulation reaching eye ; 
heels meeting or slightly overlapping; 
tibia 2 to 23 times in length from snout 
to vent ; one or two phalanges of fourth 
toe free; dorso-lateral fold present or 
SBCERABAE tS Ser os cj cgee wi rales wort Ook sug Gare R. septentrionalis, Baird. 
2. Male with internal vocal sacs; dorso-lateral fold usually very 
distinct ; vomerine teeth between choanz or just behind 
them ; first finger as long as or a little longer than second ; 
tibio-tarsal articulation reaching eye or between eye and tip 
of snout; heels overlapping ; tibia 13 to 2% times in length 
from snout to vent; one or two phalanges of fourth toe 
free. 
Dorso-lateral fold not extending beyond 
SACTARTOSION, Yow awds sa sea « PPOWE® Beate R, clamitans, Daud. 
Dorso-lateral fold extending beyond sacral 
MOOI s Horn sare adm a aatcbors, Wey shit w ads wd a « R. onca, Cope. 
3. Male with external vocal sacs; tympanum not larger than 
eye ; first finger as long as or slightly longer than second; 
heels meeting or not. 
Head as long as broad ; tibio-tarsal articula- 
tion reaching tympanum ; tibia 22 to 22 
times in length from snout to vent; two 
halanges of fourth toe free; no dorso- 
WaLeTaRLOlGe ss So ieee ss Hoe haa ow cuore R, virgatipes, Cope. 
Head broader than long; tibio-tarsal arti- 
culation reaching tympanum or eye; 
tibia 2 to 23 times in length from snout 
to vent; fourth toe webbed to the tip, 
or last phalanx free; usually a more or 
less distinct dorso-lateral fold ......., R. montezumea, Baird. 
B. Glandular dorso-lateral fold very distinct, extending to the hip 
(exceptionally interrupted posteriorly); nasal bones widely 
separated from each other. 
1. Outer metatarsals separated nearly to the base ; toes obtusely 
pointed, 3 to nearly entirely webbed ; tibio-tarsal articulation 
reaching eye, tip of snout, or a little beyond; tibia 33 to 54 
times as long as broad, 13 to 2, times in length from snout 
to vent. 
a. Male with vocal sacs. 
Head as long as broad or a little broader or 
a little longer ; interorbital space much 
narrower than upper eyelid; dorso- 
