182 University of California Publications in Zoology [Vol. 27 
phosis in the case of the toad is neither food nor enemies but desicca- 
tion. The high temperature conditions obtaining in early summer 
would quickly dry up either a small toad or a large one. But the 
small individual stands a greater chance of finding shelter than the 
large one. 
Following metamorphosis, at least two years elapse before the toad 
arrives at sexual maturity. This delay is probably to permit the 
adult, particularly the female, to acquire a certain minimum size 
before undertaking the task of egg production. 
Bufo canorus Camp. Yosemite Park Toad 
(PI. 17, fig. 51; text figs. MM, 00) 
Bufo canorus Camp (1916c, pp. 59-62, text figs. 1-4). Original descrip- 
tion, type from Porcupine Flat, 8100 feet, Yosemite National Park, 
California. 
Bufo canorus , Grinnell and Camp (1917, pp. 143-144, fig. 4). Range. 
Bufo canorus, Stejneger and Barbour (1917, p. 27; 1923, p. 24). Range. 
Bufo canorus, Grinnell and Storer (1921, p. 178). Occurrence. 
Bufo canorus, Grinnell and Storer (1924, pp. 657-660, pi. 60d, e ). General 
account of discovery, habits, and life-history. 
Diagnosis. — Size small, head-and-body length up to 71 millimeters 
(2% inches) ; parotoid glands broad, breadth equal to length of orbit, 
space between glands scarcely more than width of one gland; no 
cranial crests; dorsal coloration of males chiefly olive green, of females 
brown with large white-rimmed spots of black. 
Comparisons. — Distinguished from other California Salientia ex- 
cept Bufonidae by presence of enlarged parotoid glands on shoulder 
region; from Bufo alvarius , cognatus, and woodhousii by absence of 
cranial crests, from Bufo punctatus and Bufo boreas ssp. by narrow 
space between parotoid glands (less than width of one gland). 
Description. — Form moderate, depressed, limbs short ; head oval 
in outline from above, thick in profile; muzzle descending, steep- 
fronted; external nares nearly terminal, on slightly raised bosses, 
directed anteriorly ; canthus rostralis distinct, about two-thirds as long 
as orbit ; orbit large ; interorbital space less than half length of orbit 
(slight indication of cranial crests on some males) ; tympanic membrane 
small, slightly higher than wide, anterior margin below posterior por- 
tion of orbit ; parotoid glands relatively large, flat, subcircular, separ- 
ated by space not greater than width of one gland ; outline of lower 
jaw semicircular (male) or acutely oval (female) ; angle of jaw under 
posterior margin of orbit ; no gular fold ; fore limb short, much stouter 
in male than female ; about half of upper arm included in skin of 
body ; forearm usually longer than hand ; one large broad tubercle on 
center of palm, another much smaller tubercle at base of first finger 
(female) or two subequal palmar tubercles (male) ; fingers moderate, 
