90 Records of the Indian Museum. [Vol. XIX, 



front of the testes, the two glands spread inwards and almost reach 

 the middle line in the region of the oesophagus ; this mesial 

 extension is greatest on the dorsal side of the body. Liihe states 

 that in this region each gland may attain a breadth equal to one- 

 third of the body-breadth, but in some of the specimens examined 

 by me, they exceeded this. In the posterior region of the body, 

 behind the acetabulum, the follicles of the yolk-gland lie almost 

 entirely to the outer side of the intestinal caecum, between it 

 and the lateral margin. Anterior and posterior branches of the 

 vitelline ducts run respectively backwards and forwards in the 

 lateral regions of the body and unite opposite the posterior 

 margin of the ovary to form the main duct from each gland (fig. i 

 vitd). These dacts then pass inwards towards the middle line and 

 where they join the hi men is slightly dilated, forming the vitelline 

 reservoir from which the common duct passes to join the oviduct 

 (fig. 3 vitd.). 



The eggs are oval in shape and when first formed have a thin 

 greyish transparent capsule, but as they mature the thickness of 

 the capsule increases very considerably and the colour changes 

 to a pale yellow and eventually to a brown tint. At one pole is 

 a small but well-formed operculum with a slightly raised edge. 

 The dimensions of the eggs appear to vary somewhat in differ- 

 ent individuals and also in different stages of their develop- 

 ment. Young immature eggs in the coils of the uterus lying 

 most posteriorly are distinctly shorter and broader than the ripe 

 eggs in the terminal portion of the uterus. Immature eggs have 

 an average measurement of 0*034 nim. in length and o'o27 mm. 

 in breadth. The measurements of mature ova usually fall within 

 the limits given by Liihe, namely, a length ranging from 0*038 

 mm. (I presume that the measurement of 0*0038 as given in his 

 original description is a misprint) to 0*040 mm. and a breadth 

 of from 0*024 mm. to 0*026 mm. In certain individuals, how- 

 ever, eggs are occasionally found which show a much greater 

 range of variation ; in one young specimen containing only a com- 

 paratively few eggs, these were found to vary from 0*037 nim. in 

 length X 0*028 mm. in breadth to 0050 mm. in length X 0*021 

 mm. in breadth. Cort (1915, p. 26) has recorded an instance of 

 the eggs of Pneumonoeces similiplexus Stafford showing a consider- 

 able range of variation in dimensions in specimens obtained in differ- 

 ent localities, but the present phenomenon falls in an entirely 

 different category, and seems to be more nearly related to the egg- 

 variation described by lyciper (1918, p. 246) in a single female of 

 Schistosoma haematobium in which ovulation had only just com- 

 menced. 



The excretory system is extremely well-developed (fig. 4) : a 

 long tubular excretory-bladder (6), usuaUy containing a large 

 number of small globular refractile granules of excretory material, 

 passes forwards from the posterior end to a point about the middle 

 fo the body-length and a short distance behind the level of the 

 ovary : it is somewhat narrow in its middle third ; posteriorly 



