INTESTINAL RESPIRATION IN ANNELIDS. 739 



making the following observations I owe to Dr Annandale, who kindly sent me living 

 worms from Calcutta. 



Antiperistaltic movements are manifested in this form also. In one case they pro- 

 ceeded from the anus as far forward as the tenth segment of the posterior component 

 of a chain of two zooids, and were again obvious in the posterior portion ol the anterior 

 zooid. In another case they were observed, in the posterior component of a chain of 

 two, only in segments x.-vii. ; in the anterior component the contractions began near 

 the hinder end, and passed forwards into the anterior half of the animal, being most 

 violent in segments xiii., xii., and xi., and ending in segment x. ; the rate was sixteen 

 per minute. 



In this last instance there appeared to be a slight check to the onward advance of 

 the wave of contraction between segments xiv. and xiii. Later, the violent antiperi- 

 stalsis previously seen in segments xiii.-xi. became less marked ; and the wave of con- 

 traction often failed to pass forwards from xiv. to xiii., doing so every second or third 

 time only. 



Reversed ciliary action also occurs ; sometimes, at least, it does or does not occur 

 according to whether the anus is open or closed. In one case it reached the eleventh 

 segment of the posterior component of a chain, in another nearly to its anterior end. 



Dt^ro spp. 



It is in this genus that Bousfield {vide ante) specially noted the occurrence of the 

 reversed ciliary movement ; it can, in fact, be easily seen with the low power. In 

 specimens of this genus (species undetermined) found near Lahore, rapid and regular 

 antiperistaltic movements of the intestine were also to be observed. 



Both reversed ciliary movement and antiperistalsis occur also in a second species 

 of Dero (described but not named by me) (48). 



Other Naididse,. 



The phenomena of antiperistalsis and ascending ciliary action are also to be observed 

 in Prutina longiseta Ehrbg. ; in a Pristina which resembles in most respects P. 

 sequiseta Bourne, though, perhaps, specifically distinct (47) ; and in Stylaria 

 lacustris (L.). 



In Nais paraguayensis Mchlsn. antiperistalsis occurs ; but when I was studying 

 this form some years ago, I unfortunately made no note as to the occurrence of ascending 

 ciliary action or its absence, and I have not met with this species again since that time. 

 In a specimen belonging to the genus Naidium, the only one that I have met with, 

 and one which I have not specifically identified, I observed antiperistalsis of the usual 

 kind ; but no ciliary movement of any kind was seen, as the whole length of the 

 intestine was full of food-matter. 



On the other hand, I have not noticed either phenomenon in the two species of 



