General Account of the Ithacan Anura. 23 



Key to the Tadpoles — Continued. 



Spiracle sinistral — Continued. 

 B. Anus dextral — Continued. 



2, Upper crest not extending beyond the vertical of the spiracle — Continued. 

 b. Labial teeth |, rarely ^, etc. — Continued. 



(1) Eye nearer the snout than the spiracle — Continued. 



(a) Nostril equidistant between eye and snout. Spiracle 1.08 to 1.44 nearer 

 base of the hind legs than the snout. Labial teeth f, rarely f ; the upper 

 lateral row of teeth at least one-fourth of the length of the upper marginal 

 fringe of teeth. In ventral aspect, the sides of the body form a decided 

 angle with the tail (except in one-year-old tadpole). Tail with regular 

 round black spots, some of which arc dumb-bell-like in shape. Belly straw- 

 color or maize-yellow, not iridescent. Internasal space in the interorbital 

 space, 1.75 to 2.2. Greatest length, 145 mm Rana catesbeiana 



(6) Nostril nearer the eye than the snout. Spiracle 1 .35 to 1 .8 nearer base of 

 the hind legs than the snout. The upper lateral row of teeth never one- 

 fourth of upper marginal fringe. Tail greenish mottled with brown. Belly 

 deep cream color without or with a very slight coppery iridescence. Labial 

 teeth f, rarely |. In ventral aspect, the sides of the body gradually 

 merge into the tail. Internasal space in the interorbital space 1.25 to 

 2.1. Greatest length, 84.8 mm Rana clamata 



(2) Eye not nearer snout than spiracle. Labial teeth f . Width of muscular 



portion of the tail, 1.6 to 2.4 in depth of the tail. Internasal space 

 0.9 to 1.8 in the mouth. Belly conspicuously iridescent. 



(a) Median space between the upper lateral rows at least twice the length of 

 either one of them. Crests very dark, opaque sometimes almost solid purplish 

 black, and usually marked luith aggregate spots or blotches somewhat like 

 Rana clamata. Eye equidistant between the spiracle and the snout. 

 Internasal space less or greater (0.9 to 1.8) than the mouth. Mouth in 

 interorbital space 0.85 to 2.1. Greatest length, 74 mm .... Rana palustris 



(b) Median space between upper lateral rows equal to but not twice one of 

 them. Crests conspicuously lighter than the body, translucent, and marked 

 tvith scattered fine spots and pencilings. Eye nearer the spiracle than the 

 snout. Internasal space always less than the mouth in width (1.1 to 

 1.5 in the mouth). Belly deep cream with bronzij iridescence. Greatest 

 length, 84 mm Rana pipiens 



