Research on tlie digestive System of tlie Schizopoda 



INTRODUCTION. 



The présent work on the digestive System of the Schizopoda is part of 

 a group of investigations, on the morphology of the Arthropoda, undertaken 

 by Professer Gilson with the help of his students. 



The chief purpose of this research is to make known, with as much 

 détail and précision as possible, the internai organisation of thèse animais, 

 in order to discover whether the like and the différent characters that are 

 found between one group and another, and betw^een one species and an- 

 other, tend to bring together or to separate them, in the same way as the 

 study of their purely external characters. In other vvords, does the study 

 of their internai organisation lead us to classify them in the same way, as 

 the study of their purely external morphology? It is on the latter that even 

 the most récent Systems of classification are almost exclusively based, al- 

 though their authors are anxious to express the natural relationships of the 

 groups and the species. 



Nevertheless, we désire to impress on ôur readers that the end in view 

 of this research is in no way to bring forward a system of classification, 

 based on the study of the internai anatomy, in place of that which dépends 

 on the knowledge of the external characters. Such an intention would not 

 be justifiable. It would be less justifiable, in fact, than that which would 

 refuse a priori to give any value to the characters of internai structure. 



We wish to make it clear, that the object of thèse investigations is to 

 find out n'hctlwr there is a concordance between the variations of the in- 

 ternai structure, and tJiose of the external cJiaracters of the Arthropoda; or 



