208 



GOMPARA TI J 'E ANA TOMY 



CHAP. 





Fig. 139. Organisation of an individual of 

 Plumatella repens, with protruded crown of ten- 

 tacles, t, Tentacles ; Zo, lophophore or tentacle car- 

 rier; ?s, tentacle sheath (wall of anterior body); te, 

 constant invagiuated portion of the tentacle sheath ; 

 Z', posterior portion of body wall, covered with a 

 cuticular envelope (cell z) ; cm, anus; ed, hind-gut; Zi, 

 muscular (?) bands, which fasten the invaginated part 

 of the tentacle sheath to the body wall ; rm, larger 

 retractor muscles for withdrawing the tentacle crown 

 into the cell ; /, funiculus ; sf, statoblasts ; in, stomach 

 with caecum ; Z/i, body cavity ; g, brain. 



FIG. 133. Anatomy of Sipunculus with protruded proboscis, partly after Vogt and Jung ; 

 the body is cut open longitudinally, t, Tentacles ; g, brain ; vd, fore-gut ; rt, proboscis retractor ; 

 n, nephridia ; bmr, that portion of the ventral chord which lies in the proboscis and runs freely in 

 the body cavity ; &i?'j, ventral chord of the trunk, marking the ventral middle line ; an, anus ; and, 

 anal glands ; eil, hind-gut ; nd, accessory intestine ; abd, descending liuib ; and, ascending limb 

 of the mid-gut. 



