140 
the external pore. The shell duet (= ootype) forms nearly the whole 
length of the vagina; the internal part, free from shell giand exits 
being also of insignificant length. The transformation takes place 
where the dorsal limb of the vagina bends downwards. There are 
numerous projections of the walls of the vagina. In the proximal 
part of the shell duet (text-fig. 26, sdp) there mainly exist projeeting 
ridges formed solely by the epithelium, but in the broader, ventral 
limb of the vagina (sdd) the whole wall eontributes to the wavelike 
appearanee; thus the wall is regularly folded. In this latter part 
the vagina has its greatest ealibre, then diminishes somewhat in 
diameter when it turns upwards, but it narrows at first to a eon- 
siderable degree in the dorsal limb to form pars interna vaginae. 
The median uterine duet is short and is to a eertain extent direeted 
frontwards. From the plaee where this duet opens, a eanal holding 
the same ealibre eontinues baekwards, like a duet of Lang’s glan- 
dular vesiele, but later on it passes downwards. During its eourse the 
epithelial eanal forms a small loop in a sideward direetion. The opening 
of this duetus vaginalis (text-fig. 26, dva) to the exterior at the 
hinder border of the vaginal opening has already been diseussed. 
During its entire eourse the duetus vaginalis holds a nearly uniform 
diameter with the pars interna vaginæ. Thus there is an apparent 
differenee in respeet to ealibre between the external parts of the 
vagina and the duetus vaginalis, and this is espeeially noteworthy 
in the transverse direetion of the body (text-fig. 25). The vaginal 
opening is large and broad, the porus duetus vaginalis rather nar¬ 
row (text-fig. 25). The museularis of the duetus vaginalis is thiek 
and shows a dense grouping of the fibres. The latter eondition 
is not valid for the shell duet. The epithelium is high and eolumnar, 
and the eilia are longer and eoarser than in the shell duet. The 
duetus vaginalis does not show a beadlike appearanee as in the 
ease of Trigonoporus cephalophthalmus Lang. 
In regard to the other female organization, I need only point 
out here that the uteri are simple, unbranehed, sinuous eanals 
extending forwards as far as the pharynx. 
The new speeies approaehes most elosely the genus Crypto- 
phallus. Both are provided with a duetus vaginalis as the most 
remarkable feature in the female organization. They further agree 
in possessing simple uterine eanals. In regard to the male apparatus, 
