Ill 



PHYLUM PORIFERA 



originally simple cylinder or vase, may be looked upon as 

 an asexual mode of reproduction by budding. Asexual 



A.EusfDongia 



B.Pachychalina 



FIG. 39. Microscopic structure of the skeleton in various sponges. A, Euspongia, 

 network of spongin fibres; B, Pachychalina , spongin strengthened by siliceous 

 spicules; C, Spongelia, spongin strengthened by various foreign siliceous 

 bodies, fragments of spicules of other sponges, etc. (After Vosmaer.) 



