RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 2 1 



In the présent fig. 6, it is formed of two prominent ridges armed with 

 sharp spines reaching almost to the level of the teeth, 



This pièce becomes unpaired, a little further bacl-:, just above the 

 entrance to the pyloric chamber and terminâtes in a tongue shaped relief 

 as seen in fig. 7, covered with fine hairs. 



From the latéral aspect, fig. 3, it is seen to take an oblique direction 

 towards the pyloric chamber. 



The superior médian pièce is, therefore, in the form of a V. 



This pièce is the homologue of the médian tooth of the Decapoda. 



It is found in ail the species of the Schizopoda that we hâve examined. 



We are convinced that it plays an important rôle in the mechanism of 

 the cardiac chamber. 



Its position in the cavity, and the powerful spines which it bears, con- 

 stitute a formidable trenchant weapon, preventing the entrance into the 

 pyloric chamber of alimentary matter that has not yet been sufficiently 

 masticated. 



Th© fine hairs on the terminal portion no doubt act as a ftlter, fig. 3, 7. 



A pair of strong muscular bands are attached to the dorsal surface of 

 the stomach cavity just behind the superior médian pièce. 



■ Leaving the dorsal surface they diverge considerably, pass below and 

 at each side of the heart in a curved Une, and become attached to the 

 dorsal cuticle of the thorax, fig. l, 3. 



Curved muscular bands pass through the epithelium at each side of the 

 superior médian pièce, fig. 8, m. 



This pièce has been described by Professor Ide in Idotca. 



It is not found in Omscus, Porcellio, Armadillo, Asellus, Anilocra, 

 Gammanis, loue, Gyge and the Bopyridœ. 



Pyloric chamber. 



We must acknowledge that it is by no means easy to understand the 

 passage between the two cavities of the stomach, much less the disposition 

 and the relations between the pyloric pièces. 



In a gênerai way we may say that the posterior cavity of the stomach 

 is divided into two distinct portions, an upper and a lower. 



The upper is a cylindrical passage leading directly from the cardiac 

 chamber to the intestine. 



