41 



cles, all resemble the corresponding conditions in the 

 adult so closely that it is easy to regard this as the most 

 likely theory. May it not be that the same type of meta- 

 morphosis as that which takes place in Liriope (Brooks, 

 1885) is passed through in this genus as well? In Liriope 

 the coelenteric cavity is transformed into the system of 

 chimiferous tubules by the growth of fusion areas uniting 

 the upper and lower walls of the cavity except where they 

 are to be left separate along the lines of the canals. Fig. 

 25 ±1} a C'imera drawing of a twelve-tentacled gonosome of 

 Gonionema . which has very much the appearance of the newly 

 metamorphosed Lirio pe (Brooks, 1885, PI, 41; Kaeckel, "Die 

 Russelquallen" , PI. 12), The transformations v/hich are ne- 

 cessary to bring about the adult form from the larval are 

 the change in the coelenteron from a pouch to a system of 

 tubes, the centralizing of the diffuse nervous system to 

 form the two nerve-rings, the appearance of new tentacles 

 provided with adhesive disks and of tentacles modified to 

 the form of sense organs, from the expanded tentacular 

 ring, and the growth of the velum. The relative size of 

 the fully developed polyp and the yoimgest mediisa offers no 

 contradiction to the conception of such a process of direct 



