THE LIFE OF THE SLIGHTLY CUMPLEX ANIMALS 47 
dusa individuals, whose 
business it is to be the 
locomotive organs for the 
colony. These meduse 
are without tentacles, and 
take no food and produce 
no young. They have 
given up the power of 
performing these other 
life processes, and devote 
themselves wholly to the 
business of locomotion. 
From the lower end of the 
central stem rises a host of 
structures, among which 
several distinct kinds are 
readily perceived. One 
kind is composed of a pear- 
shaped hollow body open 
at its free end, and bear- 
ing a long tentacle which 
is furnished with numer- 
ous groups of stinging 
cells. These are the polyp 
individuals whose especial 
business it is to capture 
and sting prey and to eat 
it. These individuals are 
the food - getters for the 
colony. Scattered among 
these stinging, feeding 
polyps, are numerous 
smaller individuals with 
oval, closed body, each 
bearing a long, slender 
thread. These threads 
Seege 
Fia. 25.—A colonial jelly-fish, Physophora 
(after HAECKEL). At the top is the float 
polyp, around its stem the swimming 
medus@#, and below are the feeding, feel- 
ing, protecting, and reproducing polyps 
and meduse. 
