ANATOMICAL STRUCTURE OF KERRIA. 305 



swelling of irregular form. When fully developed the 

 diverticulum is three-lobed, the lobes being of unequal 

 size and irregular in form. It is affixed to the sperma- 

 theca at the junction of the muscular and sac-like parts. 

 This sac-like part is generally ovate and regular, very 

 much larger than the balance of the spermatheca. It 

 exhibits the peculiarity that one side of its wall is much 

 thicker than the other, the spermatozoa being massed 

 against the thinner wall, leaving the space close to the 

 thicker wall free. The muscular part of the spermatheca 

 offers no great peculiarities. The muscles are arranged 

 in two directions, the inner canal is ciliated. Contrary 

 to expectation I never found any spermatozoa in the 

 diverticula but only in the main sac-like part as has just 

 been stated. The muscular part of the spermatheca is 

 bent and twisted and the sac-like part is so bent toward 

 the muscular part, that the spermatheca is almost folded 

 on itself. The sac-like part is attached to the body-wall 

 by a bunch of strong muscular bands two or three in 

 number. There are no smaller rudimentary diverticula at 

 the apex of the spermatheca similar to those so often found 

 in species of Ocnerodrilus as for instance in Ocnerodrihis 

 Beddardi. The single lobed diverticulum is , in Kcrria j\Ic- 

 Donaldi^ always situated on one side of the spermatheca, 

 and the various lobes connect before joining the main 

 part. In one specimen the diverticulum was reduced to 

 a simple sac-like enlargement, without secondary diver- 

 ticula. The few specimens at my command did not 

 allow of ascertaining the extent of the variations of the 

 spermathecse. In two of the specimens out of the four 

 sectioned or dissected the anterior spermathecce were 

 much the shortest. In the third the spermatheca were 

 of almost equal size and in this specimen the spermathe- 

 cal diverticulum was reduced to a mere sac with no side 



