equivalent to about a fourth of the entire body length. Beyond the anterior limit of the vesicula seminalis the testicular tubule continues forwards with two or three longitudinal, but practically no obvious, lateral folds to within a distance (about equal to the length of the ejaculatory duct) of the oesophagus where it returns upon itself, the tine terminal part of the testicular tubule being found at about the centre of the body. The spicules are very unequal, the larger and more slender measuring 4.6 mm., the shorter and stouter 6 mm. In the female, the detailed arrangement of the two uterine tubules is not so easy to be followed, owing to dilatation of these organs with ripe ova. It can be seen, however, that the common conducting tube formed by the union of the two tubules opens by a transverse slit on the ventral surface of the body in the region between the juncture of the anterior fifth and the anterior fourth of the body length with the remaining portion.
The ovarian portions of these tubules are found greatly coiled with one another at the posterior part of the body cavity just in front of the rectum; the actual ends of the tubules are seen to be somewhat dilated and club-shaped.
The mature eggs have a thick smooth cuticular shell, and are much smaller than those of P. caucasica. They measure .043-6 by .035-3 mm. (Fig. 3).
The characters upon which the specific identity of the species may be established are: The large size of the adults; the peculiar construction of the lips and the simple formation of the inner tooth, the anterior edge of which is undivided. In the male, the disposition of the papillae; the internal arrangement of the testicular coils; the size of the spicules. In the female, the size of the ova, the position of the vulvar aperture, and the sharpened posterior extremity of the body.
