26 



the central body Is oomposed of two distinct parts, the distal 

 part within the cavity of the inner tuhule and a proximal part 

 connecting the inner end of the tubule with the wall of the 

 capsule. Whether the central body projects Into the outer 

 cavity of the inner tubule or ends against the shelf separat- 

 ing the inner and outer cavities of the tubule was not definite- 

 ly determined but the latter seems to be the case. 



In Pig. 66, which was drawn from a sperm in the tubule 

 of the testis that was fixed in Worcester's fluid and stained 

 in iron haematoxylin, the central body projects through the 

 apex of the capsule. This condition may have been brought 

 about by an elongation of the central body or by a shrinking 

 of the capsule. In either case it indicates that the central 

 body is more or less rigid. One should notice also that the 

 fixing fluid has caused a shrinking of the nuclear cup so that 

 it is now more like a saucer than a cup. 



In Pigs. 69 to 72 which were drawn from living sperms the 

 central body projects beyond the everted tubule like a rigid 

 rod and one gets the impression that its elongation may have 

 had something to do with the stretching of the tubule and the 

 lengthening of that axis of the sperm. The idea that the 

 central body is somewhat rigid is further supported by its ap- 

 pearance in PigB, 73 and 74, where it stands out above the 

 everted tubule. The same condition is produced in Pigs. 81 

 and 82 » Probably the strongest evidence in favor of the rigid- 

 ity of this structure is found in Pig. 75, where in lengthen- 

 ing it has pushed backwards through the wall of the cep sule 

 and pushed the nuclear cup away from the wall of the capsule. 



