536 Transactions of the Society. 



the interior of the head by the mass of eggs which the body 

 contains (Fig. 9, g s). 



Behind the pharyngeal bulb, the alimentary canal constitutes 

 a simple fusiform pocket which goes almost in a straight hne 

 through the cavity of the body (Fig. 2). The narrow ])art follow- 

 ing the pharynx may be considered as an oesophagus (Fig, 2, oes), 

 the median dilated region (Fig. 2, e) as a stomach, and the narrow 

 elongated portion which terminates in the cloaca, as an intestine 

 (Fig. 2, in). In the thin walls of the digestive tube I have not 

 succeeded in seeing the large cells of which it is usually composed 

 in the large species of Eotatoria. 



The whole length of the digestive tube is furnished with very 

 thin, long, vibratile cilia, causing a current towards the posterior 

 part. After killing the animal by compression, I saw these cilia 

 continue to move some time after death, whilst those of the buccal 

 vestibule and rotatory organ ceased immediately, a proof of the 

 influence of the will over the movement of the latter. In all adult 

 individuals the stomach (Fig. 2, e) encloses a black pulverulent 

 mass, the residue of digestion. This mass (the Uach spot of 

 Vaucher) is in a state of slow rotation which continues under the 

 action of the vibratile cilia. Small portions are detached from time 

 to time, and are carried by the cihary movement to the extremity 

 of the intestine and expelled. 



At the sides of the stomach are the two glandular organs called 

 by Elirenberg pancreatic cseca, and more appropriately by Leydig, 

 glands, or gastric appendages (Fig, 2,g g). These glands are 

 much larger in N. Wernechii than in other species of the same 

 genus. They are convex at the external, and flattened at the 

 internal surface, which is applied to the sides of the stomach from 

 the termination of the oesophagus to nearly the middle of the 

 gastric pocket. 



These gastric glands are modified with age. Colourless, fatty 

 drops are deposited in their midst, and their communication with 

 the stomach becomes larger. They are finally drawn into the 

 gastric cavity, where they are blended with a circular mass 

 surrounding the granular black mass placed in the centre of this 

 cavity. These changes are easily accounted for by considering 

 that the gastric glands are placed in two folds of the wall of the 

 stomach, which gradually unfolds with age. 



The excretory organs, sometimes considered as an apparatus of 

 aquatic respiration, are composed of a contractile vesicle placed in 

 the posterior part of the body (Figs. 2, 8, v c) and of the two sinuous 

 canals which open laterally into this vesicle (Figs. 2, 8, o s), and 

 seemed to me to ramify in the thickness of the wall of the con- 

 tractile vesicle before opening (Fig. 8, v c). 



My observations on these, however, are as incomplete as those 



