REPORT ON CORALS— EXPLANATION OF PLATES. 223 



E N. Endoderni cells. These apparently continuous with those forming 

 the lining of the canals of the coenosarcal raeshwork, XX, expand 

 into a centrally-placed mass from which the lobules spring. The 

 lobules as they approach maturity become attached by narrow 

 pedicles. 

 a One of the earliest stages in the development of a lobule. 

 b More advanced stage showing a multiplication of the contained cells. 

 c Further stage with more numerous and smaller spermatogenous cells. 

 d Further stage. The character of the contained cells is changed. 

 e More advanced stage. 



f, g, h Further stages, h, h Containing mature spermatozoa. 

 Fig. 11. Successive stages in the development of the spermatozoa of Asti/hix 

 subviridis. 



a Ordinary endoderm cell. 



d The opaque constituents of the cell are entirely condensed into the 



nucleus. 

 e Smaller similar cell produced by division of the above. 

 e',f, g Successive stages showing the development of the spermatozoon 

 from the nucleus. 

 Fig. 12. Ripe spermatozoa of Sporadopora dichotoma as seen in the living condition. 

 A vesicle is present situate between the head and commencement of the 

 filament of the spermatozoon. In the case of the lower spermatozoon of 

 the three figured, the head, which is flattened, is viewed edge on. 



PLATE XI. 



Fig. 1. Gastrozooid of Cryptolielia pudica, removed from its sac, and viewed directly 

 from above so as to be much foreshortened in the drawing. 



A. The cruciform mouth, with a lining of elongate gastric cells. 



B. Main canals given off from the outer margin of the base of the zooid 



all round. These soon branch, and join by their offsets the general 

 coenosarcal meshwork. 

 The zooid is seen to be devoid of tentacles. 

 Fig. 2. Part of a section, cut at right angles to the axis, of a cyclo-system of Astylus 

 subviridis, showing the structures surrounding the pores of the dactylo- 

 zooids at the margin of the system. 



D. Transverse section of a dactylozooid, showing ectoderm, endoderni, 

 and intermediate muscular layer. 



