1 32 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
spreading over its anterior end ; from this vesicle, secondary canals pass up into the 
surrounding tissue, these, however, cannot be traced further in sections. The bladder 
or vesicle narrows again as we pass forward, and by the time the anterior edge of the 
sucker is reached, it comes to lie between the hindermost ends of the diverticula of 
the alimentary canal. In front of this the main trunk seemed to divide into two, but 
beyond this they could not be traced. 
The Parenchyma — This packing or ground tissue consists of large cells usually 
diamond-shaped in section. They are evidently very soft, and have been pulled out 
into strand-like structures where the cuticle has been elevated. The cells contain a 
granular-looking protoplasm. The cells underlying the cuticle are much smaller than 
those of the parenchyma within, the details could not be made out, but amongst and 
between them are some obvious muscle fibres. Similar muscle fibres lie outside the gut- 
diverticula, and man}- such fibres surround the outer parts of the reproductive 
ducts. 
The Reproductive Organs. — There is a genital papilla (Fig. 2, PI. IV) situated 
in the middle ventral line about the level where the anterior quarter joins the posterior 
three-quarters. On this open close together the canal of the cirrus and the metatrema, 
the vas deferens opening slightly in front ot the latter. The whole papilla is but 
slightly projecting ; its tissue is closer and firmer than the usual body tissue. The 
distal end of the cirrus canal is muscular for a short space, and seems to have glands 
opening into it, but it soon gives a bend and opens into a thin-walled vesicle on the 
ventral surface, the vesicula seminalis, which in the specimen that was cut into sections 
contained a mass of spermatozoa. The genital papilla is on a level with the lateral 
diverticula of the oesophagus, but the vesicula seminalis lies beneath the muscular 
pharynx, just where the alimentary canal is beginning to split into two diverticula. 
Ventral to it lies the small vagina with muscular walls which, just behind the leve} 
of the opening of the cirrus canal into the vesicula seminalis, expands into the thin- 
walled uterus. 
The vesicula seminalis opens into the vas deferens dorsally, and begins to pass 
backward as a slightly coiled, thick-walled duct. This is still packed with sperma- 
tozoa. The thick-walled duct suddenly passes into a thin-walled duct, which is closely 
coiled and still packed with spermatozoa. The junction of the two is at the level where 
the uterus begins to pass dorsally ; it continues, however, to lie ventral to the coiled 
thin-walled portion of the vas deferens. The testes are double, and lie side by side, 
though one projects further back than the other. They are ventral to the uterus, 
which for a short space lies between the glands and their ducts. The testes are closely 
adpressed to one another, and it is just possible that they unite at one point. They open 
straight into the thin-walled vas deferens. Each testis is deeply lobulated. The 
glands are packed with sperm morulas in various stages of development, their darkly- 
stained nuclei giving the tissue a very characteristic appearance. 
