B. W. PRIEST ON THE CALCAREA. 107 



Grantia ciliata, var spinispicala (Carter). 

 Aphroceras ramosa (Carter). 

 Leuconia nivea (Bk.). 

 Leuconia fistulosa (Bk.). 

 Leuconia pumila (Bk.). 

 Leuconia Johnstonii (Carter). 

 Leucogypsia Gossei (Bk.). 

 Teichonella prolifera (Carter). 

 Trichogypsia villosa (Carter). 



EXPLANATION OF THE PLATES. 

 Plate VII. 



Fig. 1. Mature ovum of sponge. 

 ,, 2-3. The same in process of segmentation. 

 „ 4. Blastosphere, with dark granular cells. 

 „ 5. Free swimming larva with endodermal ciliated cells, and 



ectodermal granular cells. 

 ,, 6. Diagram, showing position of a, ectoderm ; b, mesoderm ; c, 



endoderm in wall of sponge. 

 „ 7. Group of Leucosolenia botryoides, Bk.,on weed. 

 „ 8. A small portion of the sponge enlarged. 

 ,, 9-10. Spicules of the same. 



Plate VIII. 



Fig. 1. Group of Grantia ciliata, Bk. 

 „ 2. A large variety of the same. 

 „ 3. Vei'tical section of Grantia ciliata showing the position of the 



radial tubes. 

 „ 4 to 10. Spicules of the same. 



,, 11. Leuconia nivea, Bk., encrusting rock, natural size. 

 ,, 12. Section of the same, showing ampullaceous sacs, with collared 



cells in situ, drawn from specimen. 

 „ 13 to 18. Spicules of the same. 

 „ 19. Teichonella prolifera, Carter. Upper view showing margin of 



lamina and vents. 

 t , 20. The same, lateral view of vertical section showing excretory 



canal systems and vents. (Carter). 

 ., 21-22. The two spicules of the same. 



