362 TRANSACTIONS LIVERPOOL BIOLOCICAL SOCIETY. 



from the rest of the apparent cilia. This differentiation 

 is due to the staining properties of this region, for the 

 stain which is absorbed is a nuclear stain such as 

 haematoxylin or borax carmine, whereas the cilia stain 

 only with a plasma stain. This deeply-stained zone just 

 outside the cells of the funnel is caused by the presence 

 of the heads of the spermatozoa, which always stain 

 heavily with a nuclear dye (PL IV, fig. 17, sm. h.). In 

 many of the preparations which I examined the cilia of 

 the funnel were not visible at all owing to the large 

 number of spermatozoa present, but in a few cases the 

 spermatozoa have slightly shrunk away from the funnel, 

 and in these the true cilia can be seen clearly. Their 

 length is not more than one-third or one-fourth that of 

 the spermatozoon tails. It seems to me that we have here 

 an example of the phenomenon of stereotropism, so well 

 known already in the case of spermatozoa, which appear 

 to be always attracted by any surface. If one examines 

 a funnel in the living condition one often sees a very 

 large number of spermatozoa hovering around and on 

 the funnel, and it is very possible that in the processes 

 of killing and fixing the worm they are maintained in 

 this position. 



2. The Coiled Tube. The ciliated funnel opens 

 into the tubular part of the sperm-duct, just in front of 

 the septum between segments 10 and 11. The tube, 

 therefore, perforates the septum. It belongs typically to 

 segment 11, but owing to its great length it extends 

 posteriorly through several segments, although its 

 external aperture remains in segment 11. If the tube be 

 examined under the microscope directly it has been 

 removed from the body, it will be seen as a long, delicate, 

 transparent structure with a very clearly marked cavity. 

 If one watches it for a short time it will be seen that the 



