204 University of California Publications in Zoology [Vol. 27 
Hyla arenicolor, Stejneger and Barbour (1917, p. 32; 1923, p. 29). Gen- 
eral range. 
Hyla arenicolor, Grinnell and Camp (1917, p. 145). Bang© in California. 
Hyla arenicolor, Stephens (1921, p. 6). In San Diego County. 
Diagnosis. — Size small, head-and-body length 50 millimeters (2 
inches) or less; fingers and toes with expanded adhesive discs; no 
webs between fingers; dorsal skin rough-surfaced, with many small 
papillae; side of head concolor with rest of head and body; coloration 
light or dark gray. 
Comparisons. — Distinguished from other Salientia, of California 
by expanded discs on fingers and toes and by small size of adults ; from 
Hyla regilla by average larger size (especially of females), by larger 
discs on digits, by rougher skin on dorsal surface of body and by lack 
of dark stripe on side of head through eye. 
Description. — Form stout for a Hyla ; head flat, muzzle rounded in 
profile, pointedly oval in outline from above ; canthus rostralis slightly 
longer than diameter of orbit ; external naris on canthus rostralis, 
close to tip of snout; orbit moderate in size; interorbital space flat, 
slightly wider than width of one eyelid ; tympanic membrane incon- 
spicuous, smooth-surfaced, oval in outline, wider than high, width 
not more than half length of orbit ; a thickened fold of skin extending 
from behind orbit around dorsal and posterior margins of tympanic 
membrane ; pectoral fold of skin on breast in line with axillae ; upper 
arm more slender than forearm ; one large alongate tubercle on inner 
margin of palm; sesamoid tubercles numerous; digits stout, without 
webs at base, in order of decreasing length, 3, 4, 2, 1, expanded tips 
about twice diameter of digits ; hind legs moderate ; femur shorter 
than tibia; entire foot one-third longer than tibia; tarsus about two- 
fifths length of entire foot; one elongate tubercle on inner margin of 
metatarsus ; toes stout, in order of decreasing length, 4, 5, 3, 2, 1 ; 
webs moderate, two phalanges of fourth toe free ; discs on toes wider 
than long. 
Tongue nearly filling lower jaw, attached for anterior two-thirds 
of its length ; internal nares but slightly posterior to margin of upper 
jaw and well separated ; vomerine teeth in two small clusters between 
internal nares. 
Skin on dorsal and lateral surfaces of head and body and on 
exposed surfaces of limbs and digits with many low papillae, larger, 
more numerous and more conspicuous on females than on males; 
ventral surface of body areolate. 
Ground color of dorsal and lateral surfaces (in life) varying from 
very pale gray to dark gray, usually of medium tone ('granite gray’), 
marked with irregular small blotches of darker gray ; middle of each 
eyelid crossed by a dark bar, the two sometimes meeting on inter- 
orbital space; exposed surfaces of limbs with crossbars of dark gray, 
three each on femur and tibia, two on forearm ; ventral surface of 
body, pale yellow; concealed surfaces of hind leg, orange; loose skin 
of vocal sac on throat of male, blackish. 
Description of larva. — (No specimen is available in the proper 
stage of development for adequate description of the larva [the third 
