RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 15 



Chapter I. 

 ANATOMICAL DESCRIPTIONS. 



I. Macromysis flexuosa. 



A. Study of the dissected organs. 



Speaking generally, the Schizopoda are of small size and somewhat 

 difïicult to dissect. It would be impossible to obtain an exact knowledge of 

 their internai structure by this method alone. We hâve, however, attempted 

 to separate and examine the principals parts of the stomach by simple dis- 

 section, in order to obtain an idea of their orientation. It is a rather diffi- 

 cult opération. The animal must be eut by means of a small scalpel finely 

 sharpened, and the pièces separated with fine needles under a dissecting 

 microscope. 



Yet, with ail possible care, this method is far from giving an exact 

 knowledge of the différent stomach pièces, when we hâve to deal with 

 small Crustacea. It is absolutely necessary to study a séries of sections. 

 Without this, we should never hâve a précise knowledge of the situation in 

 the stomach of the various pièces. Besides, each pièce is armed with hairs, 

 teeth or spines of différent kinds, directed in différent ways; it is impos- 

 sible, therefore, to mount them on slides without the danger of changing 

 their arrangement. We hâve, therefore, made use of both methods. To give 

 a gênerai idea of the digestive System of our animal, we will describe what 

 knowledge we hâve acquired by simple dissection. 



Paired appendages, one pair of mandibules, and two pairs of maxillïe, 

 are inserted on either side of the buccal orifice which is in form of a slit. 

 This leads into a narrow passage, the œsophagus, which runs forward 

 obliquely and opens into the ventral wall of a large cavity, the stomach. 

 We refer our reader to fig. l which represent a sideview of Macromysis 

 flexuosa, supposed to be transparent to show the disposition of the stomach 

 and the digestive glands. 



