Batrachia. 
123 
posterior border of the tympanum to the tip of the snout) is at least as long as it is 
broad at the base, except in some very old individuals. The head is considerably 
narrower in the young frog. The outline of the two sides of the head as seen from 
above is gradually convergent and practically straight as far as the nostril; from the 
nostril to the tip of the snout it converges much more rapidly and is somewhat con- 
vex, but the snout has the appearance of being pointed not very sharply. In profile 
the outline of the head slopes gradually and regularly forwards from the eye to the 
nostril and thence more abruptly downwards at an angle of about half a right angle 
with the vertical. The upper jaw projects far beyond the lower. The eyes are very 
large and prominent. 
The vocal sacs of the male are external and large, having a spherical form when 
inflated. They are situated on either side of the throat close to the gape. 
Fig. I. — Feet of frogs of the Rana tigrina group. 
K.—R. tigrina. B. — R. rugtilosa. C. — R. cancrivora. 
The vomerine teeth are very prominent and extend in two long oblique series 
from the inner front edges of the choanae. 
The dorsal surface of the body bears numerous longitudinal folds, which are 
never cotinuous for its whole, or even for half its length. Scattered among them on 
the posterior part of the back there are often small circular warts and granules, but 
these never extend as far forwards as the back of the head. The sides are more or 
less warty and the ventral surface smooth. 
The hind limbs are slender and moderately long, the tibia being about half as 
long as the head and body. The feet are broad and the toes coarse, rather blunt but 
not at all dilated at the tips. The third toe does not reach the distal subarticular 
