THE ART OF PRESERVING BIRDS. 27 
bill horizontal with the back or bottom of the rounded 
space, with the culmen (Plate IV., Fig. 1, d) nearly touch- 
ing the paper. The skin must remain in this position 
without being disturbed until perfectly dry, which in very 
warm weather, with small birds, will be in about twenty; 
four hours. : 
If this corrugated board cannot be procured, the skin 
may be placed on its back upon a flat surface, with a 
little cotton on each side of it to prevent its getting dis- 
placed. This is what is technically termed “a skin” 
(Fig. 3), and this method of making them is the best I 
have ever seen practised, and one that I have used for 
years as being the most expedient. The skins so made 
are less liable to injury, being stronger than some others, 
and are also very easily mounted. J have made in a 
single day, in the manner described, fifty skins, and with 
practice almost any one will be able to do the same; ten 
minutes being ample time for each, including the meas- 
uring. 
Before the skin is placed upon the hoard, it should be 
labelled (Fig. 3, #) with a number corresponding to the 
one placed upon the slip of paper containing the meas- 
urements, etc., marked also for the sex of the bird, which 
is done by using for the male the sign of the planet 
Mars, thus ¢@.; for the female the sign of the planet 
Venus is used, thus 2. These signs are used by naturgl- 
ists throughout the scientific world, and it is best to be- 
come accustomed to them. , 
Determining the Sex.—The sex of the bird is determined, 
not by the plumage, which will sometimes set the student 
at fault by its changes, and should never be trusted in de- 
termining the sex, but by dissection, as follows: Take the 
body of the bird after it has been removed, and cut with 
the scalpel through the ribs (Plate X. A) on the sides 
of the abdomen, thereby exposing the intestines; raise 
