POLYZOA. 



247 



seized to the mouth of the Polyzoou, and, also, that 

 this latter is situated at the bottom of a funnel of 



Fig. 18 6.— cellularia avicdlaria : a, natural size ; & and c, portions much mag- 

 nified, showing the " birds' heads;" d, a single polyzoon in its cell. 



ciliated tentacula, and calculated only to receive 

 such minute prey a-s is drawn within the ciliary vortex, 

 it is difficult to see how this can be effected. Mr. 

 Gosse has suggested a very ingenious explanation. 

 The habit of seizing a passing animal, and hold- 

 ing it with a tenacious grasp until it dies, may be a 

 means of attracting a supply of food into the vicinity! 



