AMPHIBIANS AND REPTILES. IIs 
Genus Rana Linneus.. 
The True Frogs. 
Key to the species. 
a. No black ear-patch conspicuous. 
b. Males with external vocal sacs. 
c. A glandular fold on each side of back; legs very long, heel reach- 
ing to or beyond tip of muzzle; back with 2 series of longitu- 
dinal ellipsoid blackish blotches. PIPIENS 
cc. No glandular fold on each side of back; legs short; back with 
irregular obsolete blotches. VIRGATIPES 
bb. Males without external vocal sacs. 
d. No glandular fold on each side of back; size very large. 
CATESBEIANA 
dd. Glandular folds 2 or more on back; size moderate. 
e. A glandular fold on each side of back; back spotted 
irregularly or plain; tympanum of male larger than eye. 
CLAMATA 
ee. Glandular dorsal folds 4; back with large quadrate brown 
blotches; tympanum not as large as eye. PALUSTRIS 
aa. A black ear-patch conspicuous. SYLVATICA 
Rana pipiens Schreber. 
PLATE 25. 
Leopard Frog. Shad Frog. Spring Frog. 
Head, measured to posterior edge of tympanum, 3 in body to 
end of trunk, not including hind limbs; depth 2274 normal; great- 
est width of body 234; width of head, at posterior margins of 
tympani equal to its length; snout 244; eye 3?/,; mouth 1'/,); 
width of mouth 11/;; interorbital space, measured from eye- 
sockets, 5; fore limb 144 in head and trunk; head and trunk 144 
in outstretched hind leg. Body rather elongately ovoid in pro- 
file as viewed above, and after bulge constriction forming evenly 
back. In form rather slender, or with more or less entirely ovoid 
trunk, depression both above and below slight, so that surface is 
well convex. Pelvic bones forming obtuse angle in profile along 
back about 34 length of trunk, though processes not especially 
