410 T. H. JOHNSTON. 



a comparatively long narrow " ovarian bridge," from the 

 middle of which there passes off dorso-posteriorly a fairly 

 wide but very short oviduct to the fertilising duct. The 

 total width of the gland is from 0*18 to 0*22 mm. Each 

 wing or lobe is made up of a number of branches or ovarian 

 tubes, the lumen of each being easily traced. 



The vagina opens on the same level as, and just pos- 

 teriorly to, the cirrus sac. It courses inwards and some- 

 what ventrally, as a very distinct wide tube with rather 

 strong walls, but after passing between the excretory 

 trunk-vessels, the walls become thinner. When it reaches 

 almost to the middle of the segment, it becomes consider- 

 ably narrowed, and after extending backwards for a very 

 short distance undergoes enlargement to form the spacious 

 thin-walled receptaculum seminis. This structure varies 

 in shape, being usually roughly spherical, though it may be 

 pyriform or spindle-shaped. Its position is between the 

 ovarian lobes, filling this space, and frequently extending 

 posteriorly above and behind the ovarian "bridge." Here 

 it passes into the narrow fertilising duct, a slightly con- 

 voluted tube which, after taking up the short oviduct, 

 enters the shell-gland complex. 



The vitelline gland appears as a compact rounded organ 

 placed in the midline just behind the ovary and shell-gland. 

 It is from 0*05 to 0*08 mm. broad and from 0*04 to 0*06 

 mm. long. The vitelline duct passes forwards from its 

 anterior part as a comparatively long, thick tube, to enter 

 the fertilising duct in the region of the shell-gland. The 

 vitelline gland is situated on the same dorso-ventral plane 

 as the lobes of the ovary, but slightly ventrally to the level 

 of the shell-gland. The latter organ is a fairly conspicuous 

 rounded structure lying between the ovarian bridge and 

 the vitelline gland, and dorso-posteriorly to the inner end 

 of the receptaculum seminis. Its diameter is about 0*036 

 mm. 



