8S2 



PHYLUM CHORDATA : CLASS MAMMALIA 



and ail annular absorption occurs near the base. Then the 

 antlers are shed, leaving a stump, from which a fresh but larger 

 growth takes place in the next ^-ear. The earhest (Lower 

 Miocene) deer had no antlers, thus resembhng young stags of 

 the first year ; the Middle Miocene deer had simple antlers, with 

 not more than two branches, thus resembling two-year-old stags. 

 Thus there is a parallehsm between the history of the race and 

 the individual development. 

 Examples. — Cervus, most Old World deer ; Rangifer, the rein- 

 deer ; Alces, the elk or moose ; Capreolus, the roe-deer ; 

 Hydropotes, the water-deer, without antlers ; Moschus, the 

 musk-deer, without antlers, with long sharp upper canines 

 and large musk glands in the males. 

 Giraffidae, represented by the giraffe {Giraffa camelopardalis), a tall 

 Ethiopian animal, notable for its enormously elongated cervical 

 vertebra}, and for its long limbs. It is gregarious in its habits, 

 and feeds on the leaves of trees. The lateral digits are entirely 



absent. The dental formula is ^^. In both sexes there are 



3133 

 on the forehead short erect prominences, over the union of 

 parietals and frontals, which arise from two distinct centres of 

 ossification, but afterwards fuse with the skull. In front of 

 these there is a median protuberance. The Okapi (Okapia), 

 from a West African forest, has a shorter neck, and the horns 

 are on the frontals. It links the giraffe to the extinct 

 Palceotragns. 



Antilocapridce, represented solely by the prongbuck (Antilocapra 

 americana), a North American animal, with most of the char- 

 acteristics of Bovidse. The horny sheath bears one branch, and 

 is periodically detached from the bony core. 



Bovidae, the hollow-horned Ruminants, widely distributed throughout 

 the world, but without indigenous representatives in Austraha, 

 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 alHes. 



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 



