THE SPONGES 



3503 



cutting into the sponge, large canals are seen passing down from the oscules and 

 branching into the body, and much narrower canals from the groups of pores in 

 the skin. The channels from the pores divide up into minute lacunar spaces, or 

 canaliculi, which finally communicate with the interior of small, spherical, flagel- 



SPONGES GROWING ON SEAWEED. 



a, b. Two of the Desmacidine group ; c. Spongeldia. 



(Natural size.) 



lated chambers, whose walls are perforated by pores. Each of the chambers is the 

 five-hundredth of an inch in diameter, and groups of them open each by one wide 

 orifice into a common space, or canaliculus, which joins with others to form canals 

 terminating in large oscular canals. 



