S. N. VAIDYANATHAN                                    41

                     THE PARASITIC GENERATION

No infective experiments were conducted. Only females of the parasitic
generation were recovered. They were mostly found in the first few feet of
the small intestine of the host. Up to the present time males have not been
found. It is interesting to note that the rare males, Kreis [1932] found in
the freshly passed exudates of a human case and a dog infected by him with
a human strain of Strongyloides stercoralis, are described as of the rhabditi-
form type; perhaps further investigation may reveal them in the hosts of
Strongyloides papillosus as well.

                       THE PARASITIC FEMALE

                          (Figures 7, 9, 11 and 12)

It is long and filiform as all the parasitic adults of the genus. The cuticle
bears fine striations which are resolvable only under an oil-immersion
objective. Situated around the mouth are six papillae. The oesophagus is
simple and almost cylindrical. There is no definite relationship between
the total length of the worm and the length of the oesophagus ; it may roughly
be said to vary from a seventh to a fifth of the worm. It is without a poste-
rior swelling and contains well developed oesophageal glands. The tail is
bluntly rounded and finger-shaped. The vulva, a transverse slit with rather
salient lips, is situated posterior to the middle of the body which it divided
approximately in the proportion of five to two. The gonad is double and is
composed of an anterior and a posterior loop. Sandground [1925] draws
attention to the disposition or course of the ovaries in the parasitic generation
which affords a good diagnostic feature for certain species of Strongyloides
and shows that they are twisted or simple hair-pin bends. In Strongyloides
papillosus both the anterior and posterior loops of the ovary are twisted
round the intestine which serves as the axis.