RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 49 



Euphausiidœ hâve been generally considered as closely allied to the 

 ancestral form from wliich both the Decapoda and the Mysidae hâve been 

 developed, their research on the chromatophores are in favour of including 

 the Euphausiidse among the Decapoda. 



Thèse authors tell us that D'' Hansen of Hamburg has arrived at the 

 same conclusion from the study of their appendages. 



Comparison between the stomach pièces of the Schizopoda 

 and those of the Decapoda and Edriophthalmia. 



So far we hâve been occupied simply with anatomical descriptions. It 

 remains for us to compare our research on the stomach pièces of the 

 Schizopoda, with those of the Decapoda and Edriophthalmia. 



The research of Professor Ide led him to the gênerai conclusion that 

 the stomach of the Edriophthalmia is built upon the same structural plan 

 as that of the Decapoda, and that in the Edriophthalmia the stomach 

 contains several pièces which are homologous to the principal pièces of the 

 stomach in the Decapoda, 



Our research has led us to the same conclusion in the case of the 

 Schizopoda. 



The principal pièces are five in number and are found uniformly in 

 the three groups. 



They are : 



1° The latéral paired pièces of the cardiac chamber, .S',. 



2° The latéral paired pièces of the pyloric chamber, S^. 



3° The unpaired médian pièce of the pyloric chamber, 5,. 



We give first what Professor Ide considers to be the homologies in the 

 Decapoda and Edriophthalmia. 



The latéral pièces armed with teeth in the cardiac chamber of the 

 Decapoda correspond to the upper ridges, «crêtes dentées ou hispides-, of 

 the Edriophthalmia, S,. The latéral pièces of the pyloric chamber of the 

 crayfish are homologous to the latéral pièces of the pyloric chamber in the 

 Edriophthalmia, 5,. 



The unpaired médian pièce, between the latéral pièces, of the pyloric 

 chamber of the crayfish represents the unpaired médian pièce of the 

 Edriophthalmia, «Sj. 



With regard to the stomach pièces of the Schizopoda, as far as we are 



