PLATE XXIV 



Female gonophores 



Figs, i and 2. Young growth stages in transverse section. The radial 

 canals are visible in the endoderm of the outer wall and the 

 oogonia in the ectoderm of the spadix. x 242. 



Fig. 3. Transverse and longitudinal sections in an end-branchlet of a 

 gonodendron. The section passes through the bases of a nectophore 

 and jelly-polyp (left and right centre), but below the bases of the 

 two palpons of the terminal and sub-terminal sections of the 

 branchlet. A terminal palpon is visible, bottom right. Similarity 

 in structure is shown in the nectophore and jelly-polyp — type of 

 ectoderm hypertrophied mesogloea, occlusion of canal and mus- 

 cular lamella, x 38. (See Text-fig. 29.) 



Figs. 4-7. Growth of the nectophores (seen in optical section). In 

 fig. 5 the perforation of the velum is visible ; in fig. 6 the endodermal 

 canal is occluded; in fig. 7 the gastrovascular space of the stalk 

 is wide open, and the ectoderm can be seen cupped in the endo- 

 derm. Radial and circular canals are visible in optical section. 

 Fig. 4 x 50, fig. s x 55, fig. 6 x 50, fig. 7 x 219. 



Figs. 8-15. Young male gonophores (seen in optical section). Photo- 

 micrographs to show stages in the growth of the entocodon 

 which gives rise to the cup-shaped mass of spermatocytes that later 

 covers the spadix. The smaller gonophore (fig. 13) shows the 

 earliest stage, comparable with the entocodon of the much larger 

 nectophore that grew alongside it (fig. 7) and measures o- 1 mm. in 

 diameter. In the larger gonophore (fig. 13) the base of the ento- 

 codon has started to grow over the spadix, and the primary endo- 

 derm has become reduced in thickness though it contains vestiges 

 of two or three radial canals, x 270. 



