34 
University of California Publications in Zoology [Vol. 27 
PAGE 
32'. Vomerine teeth large, in clusters on ends of indistinct 
oblique ridges between internal nares (text fig. P); 
tympanic region darker than rest of head (pi. 15, fig. 46) 
(except in pretiosa ) ; fold along upper lip usually white or 
lighter than rest of head; red usually present in colora- 
tion of ventral surface. 
35. When leg is extended forward along body, inside angle 
of bent tarsus reaches to eye or naris, never beyond. 
36. Back and top of head, marked with inky, black spots; 
a small outer metatarsal tubercle 
Rana pretiosa pretiosa 270 
36'. Back, and top of head, with dark spots not so black as 
in pretiosa; no outer metatarsal tubercle; palmar 
tubercle small or wanting . Rana pretiosa luteiventris 274 
35'. Inside angle of bent tarsus when extended forward 
reaches to or beyond naris; back and top of head with- 
out inky spots. 
37. Dorso-lateral folds indistinct; skin very smooth and 
thin; dorsal surface unspotted or with but small dots; 
size medium; head-and-body length reaching 80 
mm Rana aurora aurora 229 
37'. Dorso-lateral folds prominent; skin thick and often 
slightly roughened; dorsal surface with regularly 
placed, light-centered dark spots (pi. 15, fig. 46); 
size large, head-and-body length reaching 115 
mm Rana aurora draytonii 231 
R S 
Figs. P-S. Mouthparts of California frogs. All natural size. 
P, 'Rana aurora draytonii (no. 5612, M. V. Z.). Note general large size, 
prominence of maxillary teeth, and grouping of vomerine teeth between 
internal nares. 
Q, Rana pretiosa pretiosa (no. 5566, M. V. Z.). Note similarity to preced- 
ing in form and arrangement of teeth, but smaller size, comparing with 
next two. 
R, Rana boylii sierrae (no. 3734, M.V. Z.). Note scattering of vomerine 
teeth. 
$, Rana boylii boylii (no. 6100, M. V. Z.). Note scattering of vomerine 
teeth, and smaller size of maxillary teeth. 
(Figs. Q-S = Figs. 1-3 of Camp, 19175, p. 122.) 
