CLASS CTENOPHORA 



COMB- JELLIES 



THESE are delicate, free-swimming, generally spherical 

 bodies, resembling jellyfishes in outline, transparency, and 

 gelatinous consistency, but differing from them widely in the 

 manner of locomotion. They are called " comb-jellies " from 

 the rows of flat cilia, arranged like the teeth of a comb, which 

 run in eight meridional lines over the surface. It is by means of 

 these cilia that the animal moves through the water. The little 

 paddles are worked in unison, in single lines, or each one of them 

 can be moved independently, and they give the animal varying 

 and peculiar motions. The Ctetiophora are nearly transparent, 

 but have a prismatic coloring, caused by the waving cilia, and at 

 night they are phosphorescent. They are widely distributed, 

 being found in all seas. 



The mouth of the animal opens into a gullet which extends 

 two thirds through the length of the body. On each side of the 

 gullet is a vertical tube. The two tubes unite at the base of the 

 gullet, and from there run as a single canal to the end opposite 

 the mouth, and open to the outside through two excretory pores. 

 From the base of the gullet, where the tubes unite, two other 

 tubes extend laterally, which divide and subdivide in a horizontal 

 plane, becoming eight in number, and connect at the surface with 

 the lines of cilia; then, dividing, run in opposite directions to the 

 poles of the spherical body. The animal derives its nourishment 

 and air through this circulatory system. A nervous system is 

 situated at the pole opposite the mouth, in a small area surrounded 

 by cilia , in the center is an eye-speck, or lithocyst. 



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