12O 



ALCYON ZOOPHYTES. 



PART III. 



substance into large communities, so connected and 

 mutually dependent as to constitute one compound 



animal. Figure 

 123 represents a 

 highly magnified 

 group of Alcyo- 

 nian polypes in 

 different stages of 

 expansion. The 

 body of the polype 

 is soft, contrac- 

 tile, and composed 

 of thin, delicate 

 transparent tis- 

 sues. It has the 



Pig. 123. Alcyonian polypes highly magnified. 



form of a cone 

 resting upon its 

 base, which is generally of a firm material. Its upper 

 extremity presents a central orifice, which serves both 



for a mouth and vent, and 

 is encompassed by six or 

 eight broad, short, hollow 

 tentacles, enlarged towards 

 their base so as to meet, and 

 their edges are seen with a 

 lens only to be fringed with 

 minute hollow tubes or pinnse 

 closed at their free end. 



The narrow slit of the 

 mouth opens into the sto- 

 mach, which is a flat, short 

 sac hanging down in the 

 central cavity of the polype's 

 body, with an orifice at its 

 lower end. The stomach is 

 fixed to the internal walls 

 of the body by eight vertical 



