RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 1 1 



They are : 



1° The two latéral pièces of the anterior or cardiac chamber. 



2° The two latéral pièces of the posterior or pyloric chamber. 



3° The inferior médian pièce of the posterior or pyloric chamber. 



Pièces are found in some species which are wanting in others. Thèse 

 pièces are accessory. As Professor Ide has pointed ont, in the Edriophthal- 

 mia there is opposition between ail the pièces on the same side. This op- 

 position is notfoiuid in the Schizopoda. The latter group ressembles the 

 Decapoda, in that there is opposition between the pièces of one side and 

 the corresponding pièces of the opposite side, whilst there is no direct op- 

 position between ail the pièces on the same side. 



We leave the detailed comparison of the pièces to the end of the 

 anatomical descriptions. 



An interesting question, still unsolved, is the true function of the two 

 chambers which constitute the stomach of the Crustacea. In our con- 

 clusions we hâve given what we consider to be their functions in the 

 Schizopoda. 



It will be seen that our research in this group, obliges us to consider 

 the first or cardiac chamber, as having the rôle simply of preparing the 

 food matters by crushing and masticating, w'hilst it is in the posterior or 

 pyloric chamber, that the mixing of the food, reduced to fine particles, with 

 the sécrétions from the digestive gland takes place. 



We may mention hère, that the internai structure of Mysis ken'illei 

 difïers in no respect from that of Schistomysis ornata. From this we may 

 perhaps infer that it is but a variety of the latter, though slight différences 

 of the surface structure are found ('). 



There is a tendency at the présent day to include Nyctiphanes coiichii 

 and, in fact, the group of Euphausiidae, amongst the Decapoda. We are 

 of the same opinion. 



■ We wish to express our gratitude to Professor Gilson, under whose 

 direction this research has been carried out, at the Laboratory of Animal 

 Biology, of the Institut Carnoy at Louvain University. It was he who 

 suggested the subject of this work. We wish to thank hmi for his constant 

 aid and advice. 



(I) A careful examination of ail the external détails has been taken up by one of the workers 

 in the Zoological Laboratory in order to settle the question. 



