542 
VERTEBRATA. 
more abundant supply. On these occasions tliey unite into flocks which, often consist of from ten 
thousand to fifty thousand individuals, spreading over the face of the whole country like a swarm 
of locusts, devouring every vegetable substance that they meet with, and scarcely deviating from 
their direct path to avoid the men and dogs which endeavor to turn them into another direction. 
These vast flocks, according to Mr. R. G. Gumming, will sometimes stream along in an unbroken, 
compact phalanx for two or three hours. 
This migration is called at the Cape a Trak Bokken. So great is the number of animals in 
these migrations that those which happen to get into the rear of the troop are lean and half- 
starved before the migration is concluded, from the advanced ranks cropping the scanty pastures 
almost bare, and thus leaving those behind nearly destitute of food ; but when the journey is con- 
cluded, and the troop begins to retrace its steps northward, those which formed the van during 
the advance are necessarily in the rear returning, soon lose their plump condition, and are in their 
turn subjected to w^ant and starvation. During these migrations the herds are closely followed 
by lions, panthers, hyenas, and wild dogs, which hang upon their flanks and destroy great num- 
bers of them. There is peihaps no spectacle in nature more inspiring than a flock of these beau- 
tiful antilopes enlivening the dreary brown karroos of South Africa with their graceful motions ; 
now leaping perpendicularly upward to the height of six or seven feet, displaying at the same 
time the snowy-white marks on their croups, and anon flying over the desert with the speed of a 
whirhvind. 
It is only when disturbed or otherwise excited that they make those extraordinary springs from 
which they have derived their name ; nor do they ever display the white mark on their rump 
except on these occasions. They are said to be particularly afi'ected by changes of the weather, 
and are observed to leap more than usual before the setting in of the south wind, which, at the 
Cape of Good Hope, generally betokens stormy weather, and is always violent and tempestuous. 
When taken young, the Spring-Buck is easily tamed, and soon displays all the petulance and 
familiarity of the common goat, butting at every stranger that approaches it, and warding off 
stones or other objects thrown at it with its horns. 
THE COMMON ANTILOPE. 
The Sasin or Common Antilope — Ajitilope Bezoartica of the English Cyclopedia of Natural 
History, A. cervicapra of Pallas — is one of the most beautiful of the antilope tribe. Its length is 
four feet, its height two and a half ; the legs are long and delicate ; the body round, but light and 
well formed; the head small; the eyes large, lively, and expressive; the ears long, cylindrical, 
