44 
regions, and their fertility is of great interest in connection with climatic 
conditions, food supply, and other variable factors. The size of the 
foetuses will give some idea of the relative date of birth. 
In the beaver and the porcupine, the testes are inside the body skin 
and hidden by thick folds of fatty tissue. Fur farmers and others often 
wish to determine the sex of captured living animals, and it is well to know 
that even if the male organs are not noticeable from the outside, the testes 
may usually be detected by pinching hard and deep with the fingers. By 
pressing down hard on the abdomen in the region of the sheath, the male 
organ may be forced out and easily recognized. In skinning dead mam- 
mals of this size, the organs are, of course, readily picked out {See Young, 
1936 ). 
Never put the sex on the label unless certain of the fact. A question 
mark (?) after the sex mark should indicate any doubt on the subject, and 
even experienced collectors have to do this at times. It is a scientific crime 
to put down inferences as facts. The symbol S (the astronomical sign for 
the planet Mars) is generally used in zoology and botany to mean male, 
and $ (the astronomical sign for planet Venus) for female. 
If the age of the specimen is known, indicate it on the label. If adult, 
as shown by bones, skull, horns, or coat, it should be marked “adult” (or 
ad.), or if young, “juvenile” (juv. jv.). The age is often known by 
observing young animals with their parents. 
The measurements of specimens are of considerable importance as 
most of them must be taken in the flesh and cannot be obtained from a 
dried skin. As most modern scientific works on mammals, in this country 
as well as in Europe, give measurements in the metric system, measure- 
ments, particularly of the smaller mammals, should be taken in milli- 
metres whenever possible. It is much more convenient to compare lengths 
in millimetres than in inches and minute fractions of an inch. Rules gradu- 
ated to both inches and millimetres are easily obtained. A convenient 
way to reduce inches to millimetres, or vice versa, is to fit a stiff paper 
collar around a steel inch-millimetre rule, when by sliding the collar to 
any fixed point on the scale the corresponding equivalent in the other 
system may be read off without calculations. Where many measurements 
have to be correlated, it is convenient to have on hand a table giving 
corresponding equivalents for inches and millimetres. 
MEASUREMENTS OF MAMMALS 
For general information and for purposes of scientific comparison 
with other specimens, three ineasuremeuts should be taken of every 
mammal, namely : 
(I) Total length (abbreviated as L.) — -the distance in a straight line 
from the tip of the nose to the end of the last tail vertebra, exclusive of 
the hairs. If rigor mortis (the stiffness which sets in shortly after death) 
has contracted the muscles, the body must be stretched and the limbs 
pulled into a natural position. Place the body on its back, hold the tip 
of nose at the edge of board or table, or against a pin, or anchor it by a pin 
through the nose, hold the body down firmly, pull the hind legs out firmly 
to full length, and set a pin to mark the end of the last bone of the tail. 
The distance between these two points should be measured with rule or 
