STICHOCOTYLE NEPHROPIS, A NEW TREMATODE. 275 



diameter towards the posterior end, where it ends blindly. The intestine is 

 quite simple, and has no branches or diverticula. 



When a specimen is examined with its dorsal side upwards, and consider- 

 ably compressed, the intestine and lateral excretory canals are seen with great 

 distinctness, as there are no muscular thickenings dorsally to form suckers. 

 Fig. 2 shows somewhat diagrammatically the view thus obtained. At the pos- 

 terior end the two lateral canals terminate in muscular portions, which pass in- 

 wards behind the intestine, and unite to form a single median chamber with thick 

 muscular walls. This chamber opens in the usual way by a pore on the dorsal 

 surface, close to the end of the body. The rhythmical dilatation and contrac- 

 tion of the terminal chamber is very pronounced, and it commonly happens, 

 when the animal is under compression, that one of the spherical bodies con- 

 tained in the lateral canals passes into the terminal chamber, and is expelled 

 from the dorsal pore with some force. The appearance of the terminal part of 

 the excretory system under a high power is shown in fig. 3. 



When the living animal is very attentively examined with an objective of 

 high power, by careful focussing fine ciliated canals can be made out be- 

 tween the large lateral canals and the dorsal surface. It is probable that, like 

 the corresponding fine canals in other Trematodes, these open into the main 

 lateral canals, and are, on the other hand, in communication with the inter- 

 cellular spaces of the body-parenchyma; but owing to the opacity of the 

 tissues, I have not yet succeeded in tracing out these relations. The cilia, whose 

 motion alone enables one to trace the tubules in question, are of great length, 

 and are situated on the walls of the tubules at intervals. I have not been able 

 to discover any " entonnoirs cilids " at the ends of the branches of the system 

 of tubules, like those described by Fraipont.* I have followed the ciliated 

 tubules sometimes for considerable distances. Their course is somewhat irre- 

 gular, but maintains a longitudinal direction. They branch occasionally, but 

 the branches never extend into the median region of the body above the intes- 

 tine. I have not found any tubules on the ventral side of the body, but they 

 extend forwards beyond the anterior limit of the main lateral canals. 



I have now described the general disposition of the digestive, excretory, 

 and integumentary systems of the animal, and have hitherto mentioned nothing 

 which cannot be made out in living specimens. No reference has been made 

 to the generative or nervous systems. In the stage of the animal's history 

 which is passed within the body of Nephrops neither of these systems is 

 developed. I shall refer to structures which may be their rudiments. Special 

 sense organs are altogether absent. 



In order to examine the histological structure of the tissues, I have pre- 



* " Reck sur l'appareil excreteur des Tr£in. et Cestoides," Julien Fraipont, Arc. de BioJogie, Tom. i. 

 1880. 



