27 
rw ART OF PKESER VINO: BIRDS. 
bill' ' horizontal: with the back or bottom' 6f ■ the : rounded 
spjace, with tho culmen (Plate lY^ Eig. 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. I 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 board, 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 
Yenus is used, thus 9 . These signs are used by natural- 
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 he 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 
