158 
MARINE INVERTEBRATES 
an eye-spot on the upper rounded side, and at the other end a very 
large mouth opening into a digestive cavity, which occupies the greater 
LO ACE 
LPN) 
‘a 
(eH 
Idyia roseola, half nat- 
ural size: d, e, f, g, h, rows 
of locomotive flappers. 
part of the body. A delicate fringe surrounds the 
area about the eye-spot, and eight rows of cilia run 
from there to the oral end. It has no tentacles. Idyia 
is pink and especially highly colored at the spawning- 
time. Like other jellyfishes, their part in life is fin- 
ished when they have discharged their spawn, and the 
first September storms break them to pieces. In July 
and August they are plentiful on the New England 
coast. They appear at the surface of the water in 
the hottest part of the day, but disappear entirely 
when the water is in the least rough or the weather is 
cold or the sun overcast. Their movements are slow 
and graceful, the long axis being carried in a nearly 
horizontal position. They are exceedingly voracious, 
feeding chiefly on other Ctenophora, and often swal- 
lowing animals as large as themselves. 
I. cyanthina. This species, found on the north- 
ern Pacific coast, broadens near the center, making it somewhat vase- 
shaped. Idyopsis Clarkii, a similar genus, found in Florida, is globular. 
All these species are very beautiful, the rapid movement of the cilia giving 
them a brilliant iridescence. 
