1925] Storer: A Synopsis of the Amphibia of California 241 
Four eggs from one of the 1921 masses were somewhat larger : 
Vitelline 
Inner 
Middle 
Outer 
Egg 
capsule 
jelly coat 
jelly coat 
jelly coat 
Minimum 
2.50 
2.84 
4.50 
5.50 
9.70 
Maximum 
2.81 
2.95 
5.00 
6.40 
11.80 , 
The exact rate of development is unknown. A few measurements 
of air and water temperatures at the Thornhill Pond are as follows : 
Date (1922) 
Hour 
Water temperature 
Air temperature 
February 3 
Morning 
Pond lightly frozen 


February 9 
4:30 p.m. 
10.0° C. 
50° F. 
11.2° C. 
52° F. 
February 17 
4:00 p.m. 
11.0 
51.8 
13.5 
56.3 
February 21 
9:00 a.m. 
8.8 
47.9 
8.8 
47.9 
February 28 
9:00 a.m. 
5.5 to 7.5 
41.9-45.5 
11.0 
51.8 
March 7 
9:30 a.m. 
9.0 
48.2 
12.0 to 13.0 
53.6-55.4 
March 21 
9:00 a.m. 
11.5 
52.7 
9.5 
49.1 
Despite the rather low temperatures indicated, the eggs laid on 
February 19 and 20 contained embryos about 3 millimeters long by 
March 7, which had already hatched out of the jelly by March 14. 
At hatching, the larvae are sooty brown in color and measure 8.8 
to 10.3 millimeters in total length. The adhesive discs, stomodaeum, 
dextral anus, and two external gill filaments on each side are distinct 
at hatching. In one mass which was kept in the laboratory it was 
noted that prior to hatching the jelly coat in which the embryo was 
then contained was about 5 millimeters in diameter. Only two jelly 
coats could then be distinguished, so the innermost one may have 
become dissolved, affording the embryo greater space for development. 
For some time after hatching the larvae rest on the surface of the 
jelly, which becomes gradually softer and softer and eventually dis- 
appears. There were larvae on the jelly masses in the Thornhill pond 
up to March 27, but by April 14 tadpoles of several sizes were gen- 
erally distributed in the shallower parts of the pond. Upon April 19 
hind limb buds were detected on some of the tadpoles. Thereafter, 
due to the drying of the shallower waters at the west end of the pond, 
the larvae which survived by escaping into the main body of the pond 
were more difficult to find. Several large individuals were seen on 
June 9, the largest of those collected being 68 millimeters in total 
length. A two-hour search of the pond on August 10, when the 
aquatic vegetation was exceedingly dense, revealed only one large 
