152 ANIMAL ACTIVITIES, 
girdle then passes over the head and closes at both 
ends, forming a capsule containing the reproductive 
cells. Here fertilization takes place, and the cpps 
hatch finally into litthe worms which rapidly grow by 
the addition of new segments. 
Discovery. We find no cycs, cars, or other organs 
of sense on examining the earthworm, yet we know 
that he has to some slight extent a sense of smell, for 
he enjoys the smell of onions, cabbayes, and other 
dainty articles of earthworm dict. Possibly, too, he 
can hear a little, for he is disturbed by sounds which 
shake the earth near his burrow, though utterly dis- 
regarding the loudest noises made in the air above him. 
Although without cyes he can tell daylight from dark- 
ness; the power of doing this is said to reside in the 
first few scpments of his body in which his brain is 
found. He is probably somewhat sensitive to light in 
all segments of his body. 
His sense of touch is keenest of all and, indeed, his 
whole body seems to he a sort of fecler. 
Movements. The earthworm doubtless controls his 
own movements to a considerable extent. Ife even 
shows sig'ns of intelligence, though of i very low order. 
The most brilliant thing the carthworm does is to plug 
up the opening of his burrow to hide it from his 
enemics. For this purpose he selects his mittcrial with 
some care. 
Leaves, bits of paper, twigs, wool, and sometimes 
stones are used by the worm to make this plug, or door, 
to his hole. Ile seizes with his lips the substances to 
be used and fits them neatly to the mouth of the 
burrow. When he uses a leaf he drags it in by the 
part best suited by its shape to fit the place intended 
for it. Mr. Darwin noticed that sometimes a worm 
would let go a leaf and then try a new way of pulling: 
it into his hole. 
The worm also moves up and down his burow at 
will, and if necessary he can travel some distance from 
