1925] Storer: A Synopsis of the Amphibia of California 
181 
The spawning' season of the toad is late as compared with that of 
other water-spawning amphibians. Typically the toad lives in situa- 
tions apart from permanent bodies of water and spawns chiefly in 
temporary pools. During the earlier part of the year (January to 
March) these are as cold or colder than the surrounding air. Depo- 
sition of eggs in such locations would result in slow development at 
best. The growth of algae in such pools is slow. After the advent of 
warm weather algae increase rapidly and this affords abundant food 
for the larval toads. Furthermore, the increase in water temperature 
results in an increase in the body temperature of the larvae (which 
are practically black in color, a feature which makes for the great- 
est possible absorption of heat rays from the sunshine). There is a 
marked tendency for toad larvae to gather in the shallowest marginal 
portions of the pools, where their bodies are just barely covered by 
the water, where the water and even the mud bottom beneath the 
water are materially warmed by the sun, so that the animals get 
the greatest possible benefit from the heat (pi. 14, figs. 43, 44). The 
well-known law of Van’t Hoff and Arrhenius applies (within certain 
limits) to the growth processes of living organisms. Hence in the case 
of the toad, delay in spawning until the advent of warm weather 
results in the speeding up of the rate of development and a shortening 
of the total time in the" egg and larval stages. The species therefore 
passes through this most critical aquatic period in the least possible 
time, a matter of great importance late in the season when pools are 
apt to dry up rapidly. 
At emergence the young toad is of very small size, only slightly 
larger in actual size than the young tree-toad; relative to the size of 
the adult it is far the smallest of any of our amphibians. This small 
size is related to several factors. The delay of the spawning period 
until late in the season greatly increases the risk that one or all of the 
eggs laid by any one pair of toads will not survive the aquatic stage. 
To compensate for this the egg complement is found to be large. For 
Bufo. b. halophilns it is the largest of any of the native central Cali- 
fornia amphibians. Small size of egg and resulting larva is also 
related to rate of development. The total bulk of nutriment required 
for the aquatic larva is lessened by the small size of the tadpole. 
Small size upon transformation to the adult condition is of advantage 
in enabling the young toad to take shelter in very small crevices, 
insect burrows in the ground beneath rocks, and in other similar 
places. The greatest danger immediately subsequent to metamor- 
