240 University of California Publications in Zoology [Yol. 27 
The jelly surrounding the individual eggs when freshly laid has a 
blue hyaline tint which is lost or becomes obscured as development 
proceeds. The jelly is soft to touch yet viscid, and it is difficult to 
separate individual eggs from the general mass. The approximate 
outside dimensions, in millimeters, of eight of the masses observed on 
February 21 were as follows : 
65 X 100 X 75 150 X 100 X 100 100 X 75 X 75 
125 X 75 X 75 100 X 150 X 75 125 X 75 X 75 
150 X 100 X 75 125 X 100 X 65 
One egg mass collected February 6, 1921, had a volume of 1530 cc. 
One hundred eggs were found to have a volume of 53 cc., and the 
approximate number of eggs in the mass was therefore 2886 eggs. An 
actual count of another mass yielded 2250 embryos and infertile eggs. 
The mass collected February 18, 1923, had a total displacement of 
1180 cc., and a sample containing 417 eggs displaced 130 cc. of water. 
This would mean 3785 eggs in the mass (pi. 15, fig. 48). The seeming 
discrepancy between the figures for the first and third masses is 
explained by the fact that in the latter many of the eggs lacked the 
outermost jelly envelope which contributes largely to the bulk of the 
individual egg and hence to the mass. The large size of the sample 
used would seem to correct any error from this source. It seems 
safe to say that the egg masses of draytonii contain from 2000 to 3500 
or 4000 eggs. 
The general mass is like that of other ranas in that the jelly cover- 
ings of the individual eggs are evident on the surface of the mass: 
The individual eggs are black, heavily pigmented on the animal pole, 
and white at the vegetable pole, there being some variation in the 
amount of the white showing on different eggs. Each egg is enclosed 
in three spherical ‘jelly’ envelopes which can be readily distinguished 
even with the unaided eye (fig. CC). Measurement of a number of 
eggs from the 1922 material gave the following results (in milli- 
meters) : 
Egg 
Vitelline 
capsule 
Inner 
jelly coat 
Middle 
jelly coat 
Outer 
jelly coat 
Minimum 
2.06 
2.28 
3.10 
3 94 
7.55 
Maximum 
2.30 
2.46 
4.00 
4.93 
9.10 
Average of 9 
2.19 
2.35 
3.59 
4.45 
8.46 
