STRUCTURE OF POLYPITE. 5 



the organs may be very briefly enumerated, 

 viz. : a mouth, a stomach, and arms or tentacles 

 with which to grasp their prey. 



Stinging apparatus. In addition, the 

 tentacles are provided with stinging darts, by 

 means of which the animals overcome the 

 struggles of their victims. These darts are 

 very intesting structures, consisting of sacks 

 more or less oval in form, containing long, 

 coiled-up tubes, which are shot out like 

 harpoons and penetrate or adhere to the 

 quarry, which may be a minute worm or 

 crustacean. These dart sacks are formed 

 within a single cell. 



Darts poisonous. All experiments 

 and observations concerning these darts tend 

 to show that poison is infused into the victim. 



Body and Stomach sack-like. The 

 body of the polypite may be compared with a 

 sack or bag, the tentacles being arranged 

 around the mouth or body. 



Body wall consists of an inner and 

 outer layer of Cells, with intermediate 

 Membrane, Non-cellular. The whole 

 body wall, including tentacles, consists of an 

 outer layer of cells (" ectoderm ") and an 



