| PERISSODACTYLA 759 
from a West African forest, has a shorter neck, and the horns 
are on the frontals. It links the giraffe to. the extinct 
Palaotragus, — 
Antilocapridee, represented solely by the prongbuck (Avédlocapra 
americana), a North American animal, with most of the char- 
acteristics of Bovide. The horny sheath bears one branch, and 
is periodically detached from the bony core. 
Bovidze, the hollow-horned Ruminants, widely distributed throughout 
the world, but without indigenous representatives in Australia, 
South or Central America. The second and fifth digits may be 
completely absent, but are often represented by minute hoofs and 
supporting nodules of bone. The frontal appendages, if present, 
consist of a solid bony core growing from the frontal, and a much 
longer sheath of horn, which grows at the base as it is worn away 
at the tip. They are not deciduous, and are usually present in 
both sexes, though larger in'the males. 
Examples.—Antelope, Gazella, Capra, Ovis, Bos. 
Sub-Order PERISSODACTYLA 
Horses, Tapirs, Rhinoceros, and their extinct allies. 
The middle or third digit of fore- and hind- feet is larger 
than the others, and symmetrical on itself. It may be the 
only complete digit, as in the horse, or it may be accom- 
panied by the second and the fourth, and in the fore-foot of 
tapirs and some extinct forms by the fifth, digit. No modern 
forms have any trace of the first digit. The astragalus 
has a pulley-like surface above for articulation with the 
tibia; its distal surface is flattened and unites to a much 
greater exterit with the navicular than with the cuboid. 
The last-named bone is of less importance than in the 
Artiodactyla. The calcaneum does not articulate with 
the lower or distal extremity of the fibula. The femur 
has a third trochanter or process for the insertion of 
muscles. There are usually twenty-three dorso-lumbar 
vertebrae. . 
As to the dentition, the premolars and molars form a 
continuous series, with broad transversely ridged crowns, 
the last premolars often very like the molars. 
The stomach is simple; the czecum is large; there is no 
gall-bladder. 
The mamme are inguinal; the placenta is diffuse and 
non-deciduate. 
