1925] Storer: A Synopsis of the Amphibia of California 229 
tenanted by the species. The success of this Hyla is due evidently in 
part to its small size, its long breeding period, its loud voice and the 
relatively short period of necessarily aquatic existence. By virtue 
of small size even the adult animals are able to take shelter in narrow 
crevices where loss of moisture is reduced to a minimum. The long 
breeding period enables the animals to take advantage of spawning 
facilities whenever available and however the season in which these 
facilities may vary from place to place. The loud voice of the male, 
made possible by the enlarged vocal sac, serves to call all the breeding 
animals within a wide circle to a suitable spawning place. The males 
apparently continue in voice as long as there are appropriate facilities. 
Different breeding places may be available in different years so that 
there is no tendency toward formation of isolated breeding colonies 
with consequent development of local races, as with the frogs. A par- 
ticular Hyla may breed in one pond, say to the north of its regular 
hiding place in one year, while another year the attraction of a chorus 
in another direction may lead it to join another colony composed of 
different individuals and pool its hereditary material in a different 
complex of individuals. This free breeding would tend toward uni- 
formity of stock, such as was found to be the case by Test (1898) in 
a critical study of the variation in the species. 
Rana aurora aurora Baird and Girard. Oregon Red-legged Frog 
Bana aurora Baird and Girard (18525, p. 174). Original description, type 
from Puget Sound [= Washington?]. 
Bana agilis aurora, Cope (1889, pp. 439-440, text fig. 113), part. General 
account. 
Bana aurora aurora, Camp (19175, p. 124). Critical; range. 
Bana aurora aurora, Grinnell and Camp (1917, p. 148, fig. 5). Range in 
California. 
Bana aurora, Stejneger and Barbour (1917, p. 36). General range. 
Bana aurora, Boulenger (1920, pp. 448-452). Critical account; range. 
Bana aurora aurora, Stejneger and Barbour (1923, p. 34). General range. 
Diagnosis. — As for Rana aurora draytonii (which see), but greatest 
size somewhat less (total length up to 76.4 millimeters, 3 inches), 
dorsal skin smoother and thinner, dorsolateral folds less conspicuous, 
orbit larger and hind foot proportionately longer. 
Comparisons. — See Bana aurora draytonii. 
Description. — Form moderately stout; head narrowly oval in out- 
line from above, thin in profile; tip of muzzle slanting, overhanging 
lower jaw; external nares slightly nearer tip of muzzle than orbit, 
opening dorsally; canthus rostralis distinct, about equal to orbit in 
length; orbit large; interorbital space flat, about one-half length of 
