EMBRYONIC FISSION IN CYCLOSTOMATOUS POLYZOA. 24i 



PLATE XXIV. 



Fig. 15. — C. eburnea. A youug internode decalcified, with a developing 

 ovicell. For explanation of the letters (a, b and c) see p. 005 (Zeiss, A). 

 Figs. 16— 23.— C. ramosa. 



Fig. 16. The aperture of the same ovicell from which Fig. 6 was taken. 



The origin of the giant-cells from the thickened distal end of the 



tentacle-sheath is shown (Zeiss, F). 

 Fig. 17. Longitudinal section of an ovicell which is filled with secondary 



embryos. To the left, the primary embryo (Zeiss, A). 

 Fig. 18. Protoplasmic reticulum with giant-cells, from an ovicell at about 



the stage of Fig. 11 (Zeiss, F). 

 Figs. 19 — 21. Development of ovicell (Zeiss, A). The ovicell has in each 



case been numbered 4, in order to admit of ready comparison between 



the three stages. 

 Fig. 22. Young secondary embryo, in longitudinal section (Zeiss, F). 

 Fig. 23. Older embryo, in longitudinal section (Zeiss, F). 



