RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 55 



towards the teeth and pyloric chamber by the numerous hairs which cover 

 the surfaces of the cardiac pièces. 



In the Edriophthalmia grinding or crushing plates are generally seen; 

 thèse are formed by thickenings of the cuticle. Thèse plates are well 

 developed in Onisciis. 



Unless the thickening of the cuticle in certain régions of the pyloric 

 cavity of Nyctiphanes can be considered as grinding plates, there is nothing 

 corresponding to thèse formations in the Schizopoda. 



We consider, therefore, the cardiac chamber in the Schizopoda to be 

 an auxiliary apparatus to the appendages of the mouth, and to hâve no 

 part in the process of mixing the food with the ferments. 



In the Schizopoda that we hâve studied, the cardiac chamber cannot 

 hâve the function of a « mixer i^ because the two chambers of the stomach 

 are distinctly separated from one another, so much so that the ferments 

 arriving in the pyloric chamber from the digestive glands by the very dis- 

 position and structure of the latter chamber which is considerably depressed, 

 cannot rise to a level high enough to pass into the anterior chamber. This 

 is clearly shown by our fig. 3, 26, 32, 33, 35, 41. 



Moreover, we hâve never found any sécrétions from the digestive 

 glands in the cardiac chamber. 



Pyloric chamber. 



We hâve seen in our anatomical description of this région, that a 

 cylindrical tube formed by the meeting of opposite pairs of chitinous folds 

 fringed Avith spines, runs directly from the cardiac chamber towards the 

 intestine over the lower cavity which contains the pyloric pièces, fig. 3, 7, 

 12, 15, 17, 19, 32. 



We saw also that this tube is of a valvular nature, and that by the 

 action of muscles the folds are capable of being withdrawn. 



Our observations show that this tube is always filled with food ; some- 

 times pièces of algae are found that hâve been imperfectly masticated. 

 When the tube is closed by the meeting of the folds, nothing can pass into 

 the cavity below. 



When they are withdrawn, the smaller particles filter through the 

 rows of spines fringing the borders of the lower folds, fig. 15. 



This filtration is doubtlessly assisted by the spines upon the upper 

 borders of the médian pièce 5^, for we must allow with Professer Ide that 

 this pièce has a rocking movement. , 



