THE POLYZOA. 



391 



bodv is developed greatly in excess of the neural face. A 

 wide perivisceral cavity occupies the interval between the 

 alimentary canal and the parietes of the body, and sometimes 



■ZS 



Fig. 113.— Plumatella repens.—A single cell more magnified : a, ectocyst ; 6, endo- 

 cyst ; m, calyx at the base of the ciliated tentacula borne by the disk or lopho- 

 phore ; k, mouth; /, gullet ; g g, stomach; h, intestine ; i, anus; ?;, muscles; w, 

 nervous ganglion ;' z, statoblasts ; 0, funiculus. (After Allman.) 



the walls of this cavity are ciliated. Very generally, the 

 gastric division of the alimentary canal is connected with 

 the parietes of the body by a sort of ligament, the funi- 

 culus, or g 'astro-parietal band. Circular and longitudinal mus- 

 cular fibres, which frequently exhibit distinct transverse stria- 

 tums, may be developed in the body-wall ; and there are usual- 

 ly special muscles for the retraction of the lophophore within 

 the cell, and others for the closing and opening of the oper- 

 cular apparatus, with which many species are provided. 



dinary position of the animals. I therefore term that face of the hotly on 

 which the chief nervous centres, or the pedal ganglia ( when such are separately 

 distinguishable), are placed, neural, and the opposite hcemal. 



