ee. Mask black (sometimes absent); white 

 stripe from eye to shoulder or shorter. 

 f. Skin smooth; dorsolateral folds dis- 

 tinct; dorsum dotted or without 

 spots; head to tympanum in width of 

 head .91-1.03; size smaller 1 3/4- 

 3 1/2 inches (44-87 mm.). 

 Oregon red-legged frog. Rana aurora aurora. 



Plate LIX. 



ff. Skin rough; dorsolateral folds dis- 

 tinct; dorsum with dark light-cen- 

 tered spots; head to tympanum in 

 width of head .98-1.25; size larger 

 2 1/3-5 2 /5 inches (58-136 mm.). 

 California red-legged frog. Rana aurora 



draytoni. Plate LX. 



cc. With no mask; males with external vocal sacs be- 

 tween ear and shoulder. 

 d. Without white line on upper jaw. 



e. Upper jaw uniform or with few dashes; 

 ' size small 1 3/4-3 inches (44~74 mm.); 

 dorsum unspotted or with few spots on 

 rear like R. pipiens); with yellow on 

 under parts; males with enlarged tym- 

 pana. Nevada frog. Rana onca. Plate LXIX. 

 ee. Upper jaw mottled; size larger 2 1/2- 

 4 1/2 inches (63-113 mm.); three or four 

 rows of spots between dorsolateral folds; 

 males rarely with enlarged tympana. 

 f. Dorsal spots large, light centered; 3 

 or 4 cross bars on legs with small 

 intermediates; snout shorter; head to 

 tympanum 2.8-3.2 in L.; head to 

 angle of mouth 3- I 5"3-8 in L.; eye 

 small (9.8-12.3 in L.); intertympanic 

 space medium (3.8-4.7 in L.). 

 Northern gopher frog. Rana areolata. Plate LVIII. 

 ff. Dorsal spots small, slightly light en- 

 circled; 5-8 uniform bars on hind legs; 

 snout longer; head to tympanum 2.2- 

 2.6 in L.; head to angle of mouth 2.5- 

 3.1 in L.; eye large (6.8-10.2 in L.); 

 intertympanic space broad (2.95-3.65 



Gopher frog. Rana aesopus. Plates IV, LVII. 



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