The Sexual Conditions of Myzostoma glabrum (F. S. Leuckart). 295 



M. glabrum found on the disc (i. e. those smaller than the average 

 of the males), must also resemble the males in the enormous develop- 

 ment of the testes, and in the apparent absence of ovaries, If ova 

 were found in the small specimens on the disc, they ought 

 also to be present in individuai males of the same size, or in larger 

 males. 



But, if under these circumstances no traces of eggs were found, 

 even in the largest males, there would, I think, be no escape from 

 the inference formerly drawn as to their true nature. 



To probe the matter, the largest males i that could be found 

 were taken for comparison with the smallest hermaphrodites (from 

 the disc). 



Sections of a uniform thickness of 7133 mm were cut of ali the 

 forms examined, and their number counted by the clicks of the 

 micrometer-screw. As the aninials were killed, preserved, and pre- 

 pared in ali details in exactly the same way, and ali embedded 

 for the same length of time, the results appear to be quite trust- 

 worthy. 



The forms more particularly examined included nine males 

 (dorsicolous forms) and thirteen disc-forms or, according to my as- 

 sumption, hermaphrodites. 



In passing, it may be remarked, that repeated examination of 

 ali the sections of males made in 1884 revealed no traces of female 

 organs. 



Table 1. Males. 



size state of sexual organs 



0.5 mm ripe male elements, no eggs (fig. 12), 



0.52 - - - - - - (fig. 11). 



0.6 - - - - - - 



0.66 - - - - - - 



0.68 - - - _ _ - 



0.73 - - - - - - 



0.96 - - - _ _ _ (fig. 13). 



1 _ - _ - _ - 



1.13 - - - _ _ . (fig. 15). 



1 Known as »males< by their position on hermaphrodite forms, as previ- 

 ously defined. 



