I30 The Ameficaji Naturalist. [March. 
ment to and at the base of the beam, producing an engorge- 
ment of the vessels and deposit of calcic phosphate ; and 
that the stripping of the horns when complete resulted in 
their death and subsequent sloughing, thus originating the 
periodical shedding of the horns characteristic of the deer. 
This periodicity would depend on the periodicity of the sea- 
son of reproduction, when the horns are especially used in 
conflicts between the males (Fig. 17). 
Two species of Blastomeryx are known, a smaller, and a 
larger {B. borealis. Fig. 19), which was about the size of the 
Virginia deer. It is common in the beds of the Ticholeptus 
epoch. At the base of the horn on each side, a wing-like 
expansion extends outwards posterior to the orbit, giving a 
peculiar appearance to the anterior view. 
The extinct species belonging to the Sivatheriinae are only 
known from ,the upper Caenozoic beds of India, and they are 
among the most remarkable of the Artiodactyla. Several of 
them were of gigantic size, and their horns were of curious 
and formidable shapes. In the Sivatherium gigantemn 
Cautl. Falc, the fore legs were longer than the hind legs ; 
the forehead was concave, and furnished with a supraorbital 
horn on each side. The posterior horns were broadly palm- 
ate, and the muzzle is supposed to have been produced and 
convex above, as in the moose (Fig. 20). 
The smaller Bovidai are called Antelopes. 'Extinct spe- 
cies are numerous in the upper Caenozoic formations of Europe, 
and Asia, but 
they are want- 
ing from corre- 
sponding beds in 
North America. 
The European 
species are re- 
lated only sub- 
generically to 
gincentraland 
uth Africa. All 
of grada- 
