PHYLUM CTENOPHORA 



147 



THE DIGESTIVE SYSTEM. - - The mouth (Fig. 93, A, /) opens 

 into a flattened stomodceum, where most of the food is digested; 



FIG. 54. Cestus veneris, Venus' girdle, m, mouth; c 1 -^, ciliated bands; 

 st, st*, x l , x 2 , canals. (From Lankester's Treatise.) 



this leads to the " infundibulum " or funnel (Fig. 93, A, j) which 



is flattened at right angles to the stomodaeum. Six canals arise 



from the infundibulum. Two of these, called excretory canals, 



open to the exterior near an aboral sense-organ; 



undigested food probably does not pass through 



them, but is ejected through the mouth. The 



two paragastric canals (Fig. 93, A, 4) lie parallel 



to the stomodaeum, ending blindly near the 



mouth. The two tentacular canals pass out 



toward the pouches of the tentacles, then each 



gives rise to four branches (Fig. 93, A, 6) ; 



these lead into meridional canals lying just 



beneath the ciliated bands (Fig. 93, A, 5). 



The aboral sense-organ (Fig. 96) is a statocyst 

 or organ of equilibrium. It consists of a vesicle 

 of fused cilia (cu) enclosing a ball of calcareous 

 granules, the statolith (of), which is supported (From Lankester's 

 by four tufts of fused cilia. It is probable Jj^^"' after 

 that when the body is at an angle, the cal- 

 careous ball presses more heavily on the inclined side, and thus 

 stimulates the ciliated bands on that side to greater activity. 



FIG. 05. -- Two 



adhesive cells from 



gi, glandular por- 

 ti , on; . "; nudeus : 



sf, spiral filament. 



