HYDROID ZOOPHYTES. DO 



bottom of tlie cell : it now thickens out into a polype, 

 dilated at the bottom, and dividing, on arriving at the rim 

 of its cup, into a star of many rays, hanging over its sides 

 all round its aperture. In case of irritation, alarm, or dis- 

 content with the fluid in which it is placed, the polype can 

 collect its star-rays, or tentacula, into a bundle and with- 

 draw them into the cup. 



Campanulahia volubilis. 



"This very minute Coralline," says Ellis, "arises from 

 small irregular tubes, which adhere to and twine about other 

 Corallines, particularly the Sickle Coralline. Exceedingly 

 small tubular stalks go out from this tubular stem, which 

 supports little bell-shaped cups with indented brims. At 

 the bottom of each, where they join to the stalks, the mi- 

 croscope discovers to us a very minute spherule or little 

 ball, as in some drinking-glasses." 



EUCRATEA CHELATA. 



A minute, irregularly branched polypidom of very in- 

 teresting structure, formed by the continual addition of 

 cells, springing each one from the upper and outer rim 

 of its predecessor. The formation of a new branch, how- 



