108 NATURAL HISTORY. 
of when no Ionger needed? What is said of the Elk? Of the Rein- 
deer? Of the Axis Deer? How do the Moschide differ from the 
Deer family? What gives them their name? How is the musk ob- 
tained? What is said of the chemistry of this secretion? Compare 
the Antelopes with the Deer. What countries do they inhabit? Into 
what sub-families are they divided? What is said of the Springbok ? 
Of the Gazelle? Of the Oryx? Of the Kudu? Of theGnu? What 
are included in the family Camelidz ? Where are the two species of 
Camels found, and how do they differ? Show in what respects the 
organization of the Camel is adapted to its habits and circumstances. 
Describe its appearance. What is said of its docility? Of its mode 
of rising from a kneeling posture? Ofitsimportance to man? What 
is said of the Dromedary? What of the Llamas? What of the Gi- 
raffe ? 
CHAPTER XI. 
THE WHALE TRIBE. 
183. THE water contains both the largest and smallest 
of animals. In the sub-class now to be considered, the 
Cetacea, or Whale tribe, we find the largest animals ex- 
isting at the present time. Those monstrous terrestrial 
quadrupeds, the Elephant and the Hippopotamus, are not 
to be compared to the Whale; and even the smaller spe- 
cies of this class, the Dolphin and Porpoise, are above 
the average size of land animals. 
184. The animals of this tribe are, unlike all that we 
have as yet considered, destitute of both hands and feet. 
Though they are Mammals, they are fitted to live, like 
the Fishes, in the water. They were classified among fish- 
es by ancient zoologists, and are still spoken of as fish in 
ordinary conversation. There is one group of Mammals 
already noticed, the Seal family, which have some ap- 
proach to the Whales both in form and habits (§ 101). 
185. The general shape of the Whales is like that of 
fishes. The tail is, however, different in one respect. In 
the Whale it is flat horizontally, not vertically, as in the 
Fish. In swimming, therefore, it moves up and down, 
