238 B. W. PRIEST ON THE NATURAL HISTORY, ETC., OF SPONGES. 



Fig. 3. — Section of Grantia compressa, showing ciliated collared cells in 



situ. 



Fig. 4. — Single collared cell (Kent). 



Fig. 5. — Ampnllacious sac ehowing position of cells in some species. 



Fig. 6. — Section of Haliotis shell, with burrows of sponge. 



Fig. 7. — Sphei'ical body from Sponge (Kent), 



Fjg. 8. — Xanthidium ramosiim, 



PLATE XVIII. 

 Spicules from various Sponges of the Hexradiate type. 



