792 PROFESSOR J. STEPHENSON ON 



the last ten segments ; it very possibly existed higher up in the alimentary canal also, 

 but this could not be definitely ascertained, owing to the presence of opaque genital 

 products in this region ; it was, however, present, and very violent, in the hinder part 

 of the anterior of the two animals in course of separation. 



An experiment with carmine particles was not successful ; the animals seemed to 

 try to get away from the carmine, as if the particles irritated them. 



No antiperistaltic contractions of the intestine were observed. 



Odontosyllis ctenostoma. 



When the anus was open, the ascending ciliary motion was actively present at the 

 anus, feebler a few segments higher up the intestine ; it died away in one specimen at 

 the tenth segment above the anus ; in another it was visible for eleven segments, and 

 was then obscured by masses of f«cal matter in the intestine. 



When the anus was closed, the ciliary action ceased near the anus, but was still 

 faintly visible higher up. 



Antiperistaltic contractions of the gut were not observed. 



Eusyllis tuhifex. 



Reversed ciliary action was proceeding actively and could be observed with ease iu 

 the last nine segments ; above this level the intestine was too opaque to allow of its 

 being observed, but from the fact that the action was still proceeding strongly at the 

 point where it ceased to be visible, it may be concluded that it extended some distance 

 further up. 



The intestine was seen to contract from time to time, though infrequently and 

 irregularly ; and whenever the intestine contracted, the dorsal vessel was also seen to 

 contract. The impression given was that both structures possessed independent con- 

 tractility, though, as said, the contractions of both were always simultaneous. 



Genus Autohjtus. 



In a specimen of Autolytus pictus, in which the anus was almost closed and the 

 lumen of the hinder part of the intestine considerably contracted, ascending cihary 

 action was observed in the last few segments ; but this was only momentary, since the 

 anus was quickly closed and the lumen of the hinder part of the gut occluded. In 

 another specimen the phenomenon was not observed at all. 



In a species of this genus which was perhaps A. prolifer, the anus was closed during 

 the time the animal was under observation ; ascending ciliary action was seen in the 

 eighth, ninth, tenth, and eleventh segments in front of the anus, perhaps most 

 markedly in the ninth and tenth, though it could not be called obvious anywhere. 



