XXXVI 



INTRODUCTION. 



condition that of an organism endowed with the means of 

 locomotion, and fitted for independent being. Thus in 

 Hydra it is a mere bulging of the body-wall, between the 

 two layers of which the generative elements originate ; and 

 this, it must be remembered, is the earliest stage of all the 

 more complex forms. In Clava it is a distinct process, 



Fia\ xiv. 



V- 



I 



i , 



- 



Male capsule of Gonothyr&a Loveni. a. A gonozooid, still within the 

 capsule, b. The spermatic mass. c. The spadix communicating with the 

 cavity of the ccenosarc. '. A gonozooid, borne at the summit of the capsule, 

 discharging the spermatozoa, b'. The spermatic mass, fully developed, c'. 

 The spadix. 



containing a prolongation of the general cavity of the body, 



