GENEEA or THE ALCTONAEIA STOLONIEERA. 347 



Fig. 5. Transverse section through a polype of Clavularia australiensis, Variety A, 



showing the enormous number of zooxanthellse adhering to the endoderm, 



and the simple columnar form of the ectoderm. 

 Fig. 6. Two forms of spicules found in another specimen of Clavularia australiensis. 



Variety A. 

 Fig. 7. A specimen of Clavularia australiensis. Variety B, showing the ribbon-like 



character of the stolon at the edges. One of the polypes is fully expanded, 



but all the others are in difi'erent stages of retraction. 

 Fig. 8. Transverse section of a polype of Clavularia australiensis, Variety B, showing 



that there are only a few zooxanthellse adhering to the endoderm (compare 



C. australiensis. Variety A, fig. 5). The ectoderm is thick and vacuolated, 



the cells being irregular in shape. The siphonoglyphe is large and well- 

 defined. 

 Fig. 9. A small portion of a colony of Clavularia ramosa, growing on a ramifying 



sponge. 

 Fig. 10. The growing point of a colony of Clavularia ramosa, showing two young 



polypes. 

 Fig. 11. Three forms of spicules found in Clavularia ramosa: a, a spicule from the 



body-wall ; h, two spicules from the tentacles. 

 Fig. 12. A specimen of Clavularia flava growing on a piece of oyster-shell. 

 Fig. 13. Three forms of spicules found in Clavularia flava. 

 Fig. 14. Transverse section through a portion of the stolon of Clavularia flava, showing 



four endodermic canals in section. 

 Fig. 15. Spicule of Clavularia gar dm. 

 Fig. 16. A spicule of Clavularia viridis. 

 Fig. 17. Outline sketch of a transverse section through a polype of Clavularia viridis, 



to show the large and deep muscular ridges on the mesenteries. 

 Fig. 18. Transverse section through a portion of the body-wall of Clavularia viridis, 



showing the horny fibres, h.f., and the lacunae left after the solution of the 



calcareous spicules in the mesoglcea. 



Eeference letters used in all the figures : — Ect. Ectoderm ; End. Endoderm ; Lac. 

 Lacunse ; Mes. Mesogloea ; Muse. Muscular ridges ; Siph. Siphonoglyphe ; 

 Stom. Stomodseum ; Zx. Zooxanthellse. 



