A Mesostoma from Bloe^nfontein. 
57 
the cuticular valve-like point (6) of the penis seems to lie within the penis ; 
5 is the cavity of the penis sheath. 
The single ovary (7) lies on the side just above the end of the uterus ; 
the oviduct has two muscular portions (8 and 9), to which I shall return 
later, and an enormous receptaculum seminis (10) filled with spermatozoa. 
The hinder portion of the receptaculum is embedded in the ventral part of 
the post-pharyngeal gut. The vitellaria lie dorsal to the whole of the gut 
and are in the form of two sets of anastomosing tubes ; from each of these 
a number of minute ducts open into the two lateral vitelline ducts which 
Fm. 2. — Reconstruction of the pre-pharyngeal portion of the left testis. it; = vasa 
efferentia. 
lie close to the lateral vasa deferentia, and which open into the oviduct at 
12, Fig. 3. The common duct (14) receives accessory female ducts (13) ; 
these lie in two groups ventral to the ductus communis and open by a 
pair of ducts, but some of the oHgo-cellular glands also open independently 
into the ductus communis. Further forwards the duct enlarges to form a 
vagina (15), which has a thick sheath of circular muscles and thinner 
outer sheath of longitudinal fibres ; the vagina in both the specimens cut 
serially contains a ball of spermatozoa. There are two uteri (22) which 
