A SYNOPSIS OF 
THE AMPHIBIA OF CALIFORNIA 
BY 
TRACY I. STOEER 
(Contribution from the Museum of Vertebrate Zoology, and from the Zoological Laboratory of the 
College of Agriculture, University of California) 
INTRODUCTION 
The amphibians more than any other group of terrestrial verte- 
brates are dependent upon the presence of moisture for their 
successful existence, though different species vary greatly in the 
amount of water which is necessary for the completion of their respec- 
tive life-cycles. The perennibranchiate urodeles and the American 
Bullfrog (Rama catesbeiana) can exist only in the presence of perma- 
nent bodies of water. In contrast to this some of the nocturnally 
foraging land salamanders (Plethodontidae) need nothing more than 
the humid atmosphere afforded by a cavity in a rotted log or the 
burrow of some terrestrial mammal ; in such situations they can spend 
the daytime hours and, at the appropriate season, deposit their eggs. 
But the environmental requirements of the greater number of 
species of amphibians, at least in North America, are intermediate 
between these two extremes. They are truly amphi + bios (two-lived), 
requiring the presence of bodies of water for their egg, embryonic, 
and larval stages, but spending a certain portion of their lives out on 
the land. In some forms, such as the Spadefoot Toad (Scaphiopus ) , 
the aquatic stage requires but a few weeks; in others, such as the 
Marbled Salamander ( Dicampiodon ensatws ) , a period of several 
months is passed in the water. Some species of Salientia are able to 
exist in the adult state in localities which afford a very meager amount 
of atmospheric or ground moisture. This is the case with the Spade- 
foot Toad {Scaphiopus) and some of the species of true toads which 
