HOW ANIMALS EAT. 49 
CHAPTER VIII 
HOW ANIMALS KAT. 
1. The Prehension of Food. — (1) Liquids.— The sim- 
plest method of taking nourishment is by absorption 
through the skin. The Tape-worm, for example, has 
neither mouth nor stomach, but imbibes the juices of the 
animal it infests. Many other animals, especially Insects, 
live upon liquid food, but obtain it by suction through a 
special orifice or tube. Thus, we find a mouth, or sucker, 
furnished with minute teeth for lancing the skin of ani- 
mals, as in the Leech; a bristle-like tube fitted for pier- 
cing, as in the Mosquito; a sharp sucker armed with barbs, 
to fix it securely during the act of sucking, as in the 
Louse; and a long, flexible proboscis, as in the Butterfly. 
Bees have a hairy, channeled tongue, and Flies have one 
terminating in a large fleshy knob, with or without little 
“knives” at the base for cutting the skin: both lap, rather 
than suck, their food. ; 
Most animals drink by suction, as the Ox; and a few 
by lapping, as the Dog; the Elephant pumps the water up 
with its trunk, and then pours it into its throat; and Birds 
(excepting Doves) fill the beak, and then, raising the head, 
allow the water to run down. 
Many aquatic animals, whose food consists of small par- 
ticles diffused through the water, have an apparatus for 
creating currents, so as to bring such particles within their 
reach. This is particularly true of low, fixed forms, which 
are unable to go in search of their food. Thus, the Sponge 
draws nourishment from the water, which is made to cir- 
culate, through the system of canals traversing its body, 
4 
