53^ THE INVERTEBRATA 



to follicular tissue which supplies nourishment. Masses of cells are 

 nipped off to form the secondary embryos each of which becomes an 

 aduh. 



Classification 



Class Endoprocta (Fig. 396). Simple and archaic polyzoa in which 

 the anus is situated inside the lophophore ; without body cavity, 

 the space between gut and body wall being filled with paren- 

 chymatous tissue; with non-retractile tentacles which can be 

 covered by a circular flap of the body wall, provided with a 

 sphincter muscle; with a pair of nephridia ending in flame cells, 

 and gonads with a duct of their own. Pedicellina^ Loxosoma. 



Fig, 396. Section through an endoproctous polyzoan. Altered from Ehlers. 

 An. anus; at. atrium; ga. ganglion; g.gl. gonad; g.op. genital opening; 

 int. intestine; M. mouth; mr. sphincter muscle of circular flap of body wall; 

 oe. oesophagus; par. parenchyma; st. stomach. 



Class EcTOPROCTA. Polyzoa with anus outside the lophophore; with 

 a coelomic body cavity and a lophophore retractile into a tentacle 

 sheath; without definite excretory organs. 

 Order Phylactolaemata. Freshwater Ectoprocta with a horseshoe- 

 shaped lophophore, an epistome and statoblasts. Plumatella, 

 Cristatella. 



