268 J. G. WALLER ON CLIONA CELATA, ETC. 



Fig. 4. — Osculum of sponge dosed ; the porous system in the thick ring of 



net-work around it. 25 diameters. 

 Fig. 5. — Excavated channels in section of Haliotis, in possession of Mr. 



Kitton, with a group of spicules brought close to them for 



comparison of size. 125 diameters. 

 Fig. 6. — Development of sponge from gemmule (?). 500 diameters. 

 Fig. 7. — Gemmnles (?) of the sponge, with budding development About 



85 diameters. 

 Fig, 8. — Annelid found on fragment of a perforated shell. 500 diameters. 



