36 
Moreover, the distance from the female genital pore to the post- 
erior margin of the body is not less than Ve the body’s length. Like- 
wise the two genital pores lie very close to each other in this case, 
Another member of Stylochidae is the genus Cryptophallus, 
characterized by the development of a ductus vaginalis. As this 
canal is also derived from the duet of Lang’s glandular vesicle, I 
am classing this genus with Group II. The figure obtained for 
the location of the female genital pore here, in C. wahlbergi Bock, 
is mueh smaller, or Vio. Exaetly the same Figure is obtained for 
an undescribed Crypfop/ia//MS-species from Amboina. In both these 
species one might consider as the „causa agens** for the backward 
move the unusual extension of the pharyngeal pocket, which has 
reached such dimensions that it will also cover the male copulatory 
organ, a condition that is otherwise unknown in the Acotylea. As 
a result, the two genital pores have become more separated. 
In the genus Bergendalia, which I brought close to Stylochidae 
(Bock 1913), there is likewise a ductus vaginalis. In regard to 
the location of the female orifice, the genus oceupies a middle po¬ 
sition between Idioplanoides and Cryptophallus. 
A tendency in Stylochidae to move the female aperture back- 
wards has been mentioned above. It is unmistakeable within Group I, 
as the location is exelusively caudal. This location does not only 
concern the genital pores, but also the entire vagina, which, conse- 
quently, is very short (see, for instance, Stylochus pusillus and 
Parastylochus astis (Bock 1913, text-fig. 23 and 15)). Meixneria 
alone deviates through the frontal location of the entrance of the 
uteri in the vagina, the ventral limb of which thus acquires an 
extreme length (Bock 1913). 
The organization of the female apparatus varies mueh more 
within Group II. We consequently encounter greater variations in 
the location of the female genital pore in the genera of this group. 
In the Stylochids provided with Lang’s glandular vesicle the 
inner end of the vagina is at a marked distance from the posterior 
margin of the body. This is also true in the case of the genera 
Idioplanoides and Limnostylochus, where the vesicle in question has 
the shape of a horse-shoe with forwardly directed diverticula. This 
unusual shape can plausibly be explained as a backward move of 
the vesicular duet, causing the compression of the vesicle in the 
