THE FIGURES. 123 



intestinal tube is seen the commencing development 

 of tlie third generation {the perfect females^ 



Fig. 53. Two perfect/eii/^ö/e^, which are protruded through 

 the operculum of the ''nurse;'' in one of them is 

 seen the fully-developed egg, which may also be 

 distinguished even before the female quits the " 7mrs- 

 ing animal" (vide fig. 52) ; in the other, the young 

 are on the point of escaping into the water. 



Figs. 54-57. Shoto the metamorphosis of the young, and 

 the toay in which a neio polype stem is founded, toge- 

 ther with the origin of the " parent-nurses/' 



Fig. 54. The oval ciliated, young polype (in the water). 



Fig. 55. The young polype, after it has affixed itself 

 and become contracted into the form of a disc. 



Fig. 56. The same, rather older; the disc is beginning 

 to divide into several portions, and presents in the 

 centre a small tubercle. 



Fig. 57. The same, after this rounded tubercle has in- 

 creased in height, and has formed the lower part of 

 the stem of the compound polype. 



