RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 2 3 



Thèse folds continue as far as the intestin ; we shall see later how 

 they terminate. 



The lower cavity is of a very complicated structure, and very difficult 

 to understand without following many sections in différent directions. It 

 contains the large unpaired pièce 5, which is seen in longitudinal aspect 

 in FiG. 3. 



Its base occupies ail the floor of the cavity. 



It rises gradually from the anterior ventral surface in a curved line. 



Near its extremity it becomes slightly concave and terminâtes freely 

 in a spin-like formation, fig. 3, 16, 18. 



Its upper border is fringed with sharp spines, reaching almost to the 

 roof formed by the folds SJ. 



A horizontal section through the pièce S^ is seen in fig. 14. 



The posterior surface is wide, and occupies almost the entire diameter 

 of the cavity in front of the opening of the digestive glands in ^/. 



In FIG. 15 the pièce 5, is seen in transverse section in the form of a 

 column rising from the floor of the cavity. 



The summit is triangular shaped; the sides are covered with short 

 fine hairs. 



A bouquet of spines is seen on the upper border. 



At its anterior end, where it rises from the floor of the chamber, the 

 summit is concave, fig. 7; in fig. 15 it is a sharp ridge ; near its terminal 

 point it becomes concave again, fig. 16, 18. 



The epithelium of the inferior médian pièce 5j has been very much 

 contracted in our figures by the fixing solutions. 



On the latéral faces of the pièce 5j, fig. 15, a transverse section of two 

 grooves is seen on the right and the left, cf. fig. 16, g}-. 



The latéral aspect of thèse grooves is shown in fig. 9. 



The upper grooves are separated from the lower by chitinous ridges 

 bearing an immense number of sharp spines that lie close to one another 

 like the teeth of a comb. 



The borders of the lower grooves bear also Unes of spines which are a 

 little shorter than the upper spines. 



Fig. 10 is the drawing from a dissected pièce. 



The ridges or borders of the grooves are seen running in curves along 

 the side of the pièce S-, faced by the comb-like apparatus of spines. 



