230 RADIATES: JELLY-FISHES. 



digestive cavity, or stomach, occupies a large part 

 of the interior of the animal. In summer it some- 

 times appears in such swarms as to tinge large patches 



Fig. 473. Pleurobrachia. 



of the sea with a delicate rosy hue. It is very vora- 

 cious, and feeds mainly on other jelly-fishes, sometimes 

 capturing those nearly as large as itself. 



TRUE MEDUSAE, OR DISCOPHOR^. 



These have the body. in the form of a hemispheric 

 disk, more or less flattened. Of these disk-shaped me- 



