242 University of California Publications in Zoology [Vol. 27 
tadpole of this species which, unfortunately, escaped capture. The 
time at which the larvae in this pond metamorphose into frogs is 
unknown. Mr. D. A. Jones reports finding young frogs there on 
November 20, 1922, but these in all probability had transformed at 
some time earlier. The history of the frogs in the Thornhill pond 
unfortunately ends here. 
Observations in other localities make it possible to piece out the 
life-history. Draytonii occurs in numbers on the fresh- water marshes 
just west of Point Reyes Station, Marin County, where Olema Creek 
flows down to the southern end of Tomales Bay. Young frogs of this 
species which had evidently transformed from tadpoles of the current 
season’s growth were seen in numbers in the fresh-water pools of the 
marsh on August 26, 1922. No larvae were observed on this date 
although no careful search was made for them. A visit to the same 
marshes on May 5, 1923, revealed many larvae, of various sizes up to 
a total length of 83 millimeters; but no young frogs which could be 
ascribed to the 1923 crop of tadpoles were seen. One of these larvae 
kept in an aquarium at Berkeley completed its metamorphosis about 
June 15, while others were still typical larvae on that date. 
In the Arroyo Seco, Los Angeles, opposite Avenue 66, Mr. Alden 
Miller at my request collected samples of the draytonii population of 
larvae during the spring of 1923. Part of these were taken from the 
same pool which contained hatching larvae on January 21, and all 
were taken within a quarter-mile of that pool. The following table 
gives the measurements of this material, as made by the writer. 
Date 
Total length in millimeters 
(1923) 
Minimum 
Maximum 
Average of 
ten largest 
Remarks 
April 7 
April 15 
April 22 
April 29 
24 
14 
23 
26 
56 
58 
58 
62 
50.6 
Smallest not sought for; hind 
limb buds just appearing 
May 6 
22 
71 
65.6 
One completely metamorphosed, 
head-and-body length 30 mm. 
May 13 
22 
72 
62.7 
May 27 
46 
72 
67.0 
June 13 
36 
75 
69.2 
June 20 
45 
80 
73.0 
Several metamorphosing, others 
with hind legs well developed; 
head-and-body length 25 to 28 
mm. 
