42 



ZOOLOGY 



cells may be noticed withdrawing their pseudopodia, and passing 

 into a spherical resting condition. These form the ova. Others 



Fig. 33. — Various forms of Sponge spicul^. 



divide up into an immense number of spermatozoa (Fig. 35), each 

 with a head and long vibratile tail. In Grantia lahyrinthica 





Fro. 34. — Sections tlu-ougli horny fibre of Dendrilla. A, Longitudinal section; 

 layers of spongin, surrounded by a layer and surmounted by a cap of spongo- 

 blasts ; a, fibrous sheath. B, The same in transverse section. After Von 

 Lendenfeld. 



Dendy has described the ripe ova making their way through the 

 mesoderm to the epithelium of the inhalent canals, and passing 



