BRYOZOA. 



75 



the same animals, more rarely in different individuals. The ovaries 

 which are filled with many ova are placed on the inner surface of the 

 anterior part of the body wall ; while the testes with their seminal 

 capsules are developed either on the upper part of the funiculus or 

 near the point of attachment of the latter to the body wall. Both 

 kinds of generative products are de- 

 hisced into the body cavity where 

 fertilization takes place. From the 

 body cavity the fertilized egg passes 

 either into a bud of the body wall 

 (AlcyoneUa), or, as in marine Bryozoa, 

 into an external appendage, - - the 

 ocecium. 



The name statoblast (fig. 549) was 

 given by Allman to certain peculiar re- 

 productive bodies, which were formerly 

 regarded as hard-shelled winter eggs, FIG. 548. s<- /<<,.<-,<, iinna fero.c (after 



i i i . -, Allman). Vi. Vibracula. 



but by him were recognised to be 



germs which are not fertilised. The statoblasts are found only in 

 the fresh- water forms. They arise from masses of cells which 

 appear principally towards the end of summer on the funiculus 

 (fig. 545). They usually possess a lens-like, biconvex form, and 

 are covered by two watchglass-shaped, hard chitinous shells, the 

 edges of which are often enclosed by a flat ring formed of cells 



containing air (float), and some- 

 times (Cristatell(i) provided with a 

 crown of projecting spines (fig. 549). 

 A very important part of the 

 reproduction is effected by buds 

 which remain permanently attached. 

 The process of budding begins very 

 early in life, before the development 

 of the embryo is completed, and 

 gives rise to the formation of 

 colonies. Parts separated off from 

 the colony are rarely able to produce new colonies (Cristatella, 

 Lophopus). 



The development is always connected with a metamorphosis. The 

 budding always begins in the embryo. In the fresh-water forms, 

 after the alimentary tract and tentacular apparatus have made their 

 appearance, a second alimentary canal and tentacular apparatus arise, 



FIG. 549. Statoblasts of Ci-istatdla mucedo 

 (after Allman). a, From the surface; 

 b, from the side. 



