208 



COMPARATIVE ANATOMY 



CHAP. 



Fig. 139. — Organisation of an individual of 

 Plumatella repens. "witli protruded crown of ten- 

 tacles, t. Tentacles ; lo, lophophore or tentacle car- 

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

 constant invaginated portion of the tentacle sheath ; 

 hn, posterior portion of body -wall, covered with a 

 cuticular envelope (cell s) ; au, anus ; ed, hind-gut ; li, 

 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 ; ^^, statoblasts ; m, stomach 

 with csecum ; Ih, body cavity ; g, brain. 



Fig. 138.— 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 ; 

 71, nephridia ; 6mr, that portion of the ventral chord which lies in the proboscis and runs freely in 

 the body cavity ; hmri, ventral chord of the trunk, marking the ventral middle line ; an, anus ; aiid, 

 anal glands ; ed, hind-gut ; nd, accessory intestine ; dbd, descending limb ; aud, ascending limb 

 of the mid-gut. 



