398 THE WORLD OF THE SEA. 
running in the neighbourhood of the vertebral column. It would 
appear that these veins serve the purpose of a reservoir for the 
blood, during the time that the animal is beneath the surface of 
the water, thus keeping the most important organs from being 
overcharged. As soon as the whale reaches the surface and 
breathes, the veins discharge themselves, emptying their contents 
into the lungs, and the full process of circulation is renewed. 
The whales live in troops, or “schools,” frequently very numerous. 
There are about 100 species. The cetacea are either carnivorous 
or herbivorous ; the latter kind frequent the neighbourhood of the 
shore, moving gently among the marine vegetation. They graze 
like ruminants, thus forming an exception to the general rule. 
Most of the species when they suckle their young—for strange 
as it may seem, the whale performs this office—place themselves 
in an upright position, with their upper part above the water ; 
they then embrace their offspring in their fins, holding it to their 
breast. So much does this resemble the mode in which our 
infants are nourished, that whales have been called sea women, 
marine nymphs, sirens, &C. 
