1925 J, Storer: A Synopsis of the Amphibia of California 
25 
MEASUREMENTS 
All dimensions of specimens given in this paper are expressed in 
millimeters. In order that the measurements of the large number of 
specimens used might be strictly comparable, a definite method for 
taking each dimension was decided upon at the beginning of the work. 
The methods used are described below for the benefit of other workers 
in the field. All measurements were made by the writer. A vernier 
caliper reading to 0.1 millimeter was used for taking all measurements 
except those of the hind feet of toads and frogs and the body and tail 
lengths of salamanders. The measurements of the mouth parts of 
Salientian larvae and of the various parts of eggs were made by the 
use of an ocular micrometer in a microscope at magnifications varying 
from X 16 to X 18. 
Unless expressly indicated otherwise, all the measurements given 
beyond were made on preserved specimens. The dimensions are in 
most instances somewhat less than they would have been in the living 
or freshly killed animals. The degree of shrinkage varies in different 
individuals, the greatest alteration being in the total-length measure- 
ments of salamanders and the head-and-body length of toads and 
frogs. In a few instances where the specimens happened to have been 
measured when fresh and again after preservation, the exact amount 
of shrinkage w T as determined. In some specimens the decrease was 
less than 2 per cent, in others as much as 10 per cent, the average 
being about 7 per cent. Specimens distorted in preservation were 
straightened as well as possible before taking the measurement of total 
length. Variations in successive readings of such measurements as 
total length and length of tail may vary as much as 0.5 millimeter on 
animals over 40 millimeters in length. The shorter measurements 
can be made with a higher degree of exactitude. 
In, the tables of measurements given under the several species I 
have not thought it desirable to average the measurements. Each 
species of amphibian has a general maximum size toward which it 
grows, yet the general population of adults within a species does not 
attain to that narrow compass of variation seen in some species of 
birds and mammals. 
