THE CQLENTERATES 41 
closely packed with innumerable lasso-cells, which may be 
thrown out through openings in the body wall when the 
animal is attacked. Lasso-cells are also very numerous on 
the tentacles, which are thus to some extent defensive, but 
are chiefly active in capturing the crabs and small fish 
which serve as food. 
The partitions also carry eggs which may undergo the 
first stages of their growth within the body, and when 
finally able to swim 
are sent out through yy 
the mouth opening 
by hundreds to seek 
out favorable situa- 
tions, there to set- 
tle down and re- 
main. In some spe- 
cies the young may 
sometimes arise as 
buds, as in Hydra 
(Fig. 24), and in 
others the animals 
have been described 
as splitting longi- 
tudinally into two 
Fig. 25.—Longitudinal section through the body of a 
equal-sized young. sea-anemone. 0¢, esophagus; m. f., mesenterial 
41. Corals.—The filaments ; 7., reproductive organs. 
coral polyps also 
belong to this group, showing a very close resemblance to 
the sea-anemones. In most cases they develop a firm skel- 
eton of lime, commonly known as “coral,” which serves to 
protect and support the body. Ina few species the polyps 
throughout life are solitary, and with skeleton comparative- 
ly simple (Fig. 24); but the larger number of species be- 
come more complex by developing buds, which retain their 
connection with the parent, and in turn produce other out- 
growths with the ultimate result that highly branched 
( 
mf. r 
