RESEARCH ON THE DIGESTIVE SYSTEM OF THE SCHIZOPODA 39 



The front part of the dorsal wall of the cardiac chamber possesses a 

 small pocket formed by a pair of folds, fig. 35, p. 



Thèse folds formed of a double layer of cells extend some distance in 

 the cavity. 



In FIG. 36 they are seen attached to the ventral wall of the cavity, 



At the anterior end, however, they lie close together constituting a 

 maze-like formation which is difficult to follovv terminating at the small 

 pocket. A vertical section through the terminal portion of the folds is seen 

 in FIG. 35. 



Occasionally the interior of the folds are much distended with blood 



plasma. 



The cavity of the cardiac chamber is more elongated in the vertical 

 direction than in our type, fig. 37, 38, 39, 40. 



The plates 5^ are attached vertically. 



The saw-like teeth of our type, fig. 5, /, are not found in Siriella. 



The corresponding teeth are in the form of hooks, fig. 38, /. 



Strong teeth similar to those in fig. 6 are found in the correspon- 

 ding situation in Siriella, fig. 39. 



The ridge c terminâtes in a point behind which are inserted the Con- 

 necting folds, bi\, fig. 35. 



The médian pièce 5, possesses three pairs of latéral grooves, fig. 40. 



The stiff spines on the ridge of 5- are wanting; in their place a row 

 of plumose hairs are found. 



As we hâve already observed, the first pair of dorsal tubes of the 

 digestive gland are projected forwards above the cardiac cavity, fig. 36, gl. 



The dorsal diverticulum is only slightly developed and is unpaired. 



The intestine is much wider than in our type; in fig. 35 the chitinous 

 cuticle has been detached by the fixing solutions. 



In the neighbourhood of the stomach in Siriella numerous blood lacunes 

 are found, fig. 37, 38, 39, 40, bl. 



From the descriptions we hâve given of the last two species, it would 

 seem that they are closely allied, for in both the cardiac chamber possesses 

 folds, both hâve the remarkable disposition of the first dorsal tubes of the 

 digestive gland, and both possess three pairs of grooves in the médian 

 pièce S^. 



Several of the glandular ridges are found in each of the long tubes of 

 the digestive gland, fig. 48. 



