GEMMULES OF THE SPONGE. 37 



distance. They soon, however, become languid, and 

 in the course of a few hours they cease to move. 

 Spicula now begin to make their appearance in the 

 transparent film ; and in a few weeks after the gem- 

 mule has become fixed, these spicula become aggre- 

 gated into bundles : at particular places, towards the 

 centre, they soon present circular arrangements, and 

 distinct openings are at length perceptible by the aid 

 of a microscope in these enclosed spaces. The ova 

 now spread and enlarge in every direction, and even 

 before they exceed a line in diameter, evidently pre- 

 sent through the microscope a marked resemblance to 

 the parent sponge. 



