c. Size larger 2 1/3-4 I / 2 inches (58-115 mm.); no 

 outer sole (metatarsal) tubercle; no stripe on 

 upper jaw; throat and lower jaw uniform or 

 cloudy; hind legs shorter (.65— .69 in L.); tibia 

 shorter (1.86-2 in L.). 



Rana tarahumarae . Plate LXXVIII, 



cc. Size smaller 1 3/ S~3 3/8 inches (39-84 mm.); 

 outer sole (metatarsal) tubercle; stripe on upper 

 jaw present or obscure; throat and lower jaw 

 spotted; hind legs longer (.57— .66 in L.); tibia 

 longer (1.61-1.88 in L.) 



Yellow-legged frog. Rana boylii. Plates LXI-LXIII, 



bb. Dorsolateral folds distinct full length of body (folds 

 not conspicuous in R. aurora.) 

 c. With mask to angle of jaw (sometimes less con- 

 spicuous or absent in R. aurora); males with no 

 external vocal sacs between ear and shoulder; rear 

 of femur finely dotted and without heavy spots, 

 o. No red or yellow on the under parts; mask 

 black; size small 1 1/6-3 T A inches (29-82 

 mm.); tympanum larger (1 1— 1 5 in L.). 

 e. Dorsal color usually a mid-band of darker 

 color within light dorsolateral folds; mid- 

 dorsal light stripe present or absent; 

 breast more spotted. Hind leg short (.62- 

 .75 in L.); tibia short (1.93-2.3 in L.); 

 tibia usually equals foot. 

 Northern wood frog. Rana cantabrigensis. Plate LXIV. 



ee. Dorsal color between dorsolateral fold 

 usually like dorsum; no mid-dorsal stripe; 

 breast usually without spots; hind leg long 

 (.53-62 in L.); tibia long (1. 6-1. 88 in L.); 

 tibia longer than foot. 



Wood frog. Rana sylvatica. Plate LXXVII. 



dd. Some red or yellow on the under parts; size 

 larger 1 4/5-3 4/5 inches (45-95 mm.). 

 e. Mask brown; inky spots on back some- 

 times light centered; white stripe from 

 snout to shoulder; tympanum small (14- 

 19 in L.). 

 Western spotted frog. Rana pretiosa. Plate LXXIV. 



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