THE ANATOMY OF ONCHOLAIMUS VULGARIS, BAST. 125 



(PI. 7, fig. 5, sj).) with their accessory piece, with the 

 muscuhiture which governs them and assists in expelling 

 the sperm. Lying dorsal to the cloaca a muscular mass 

 (PI. 7, fig. 6, 2^^-) 's to be found, imbedded in which are the 

 spicules and accessory piece. The fibres run in the same 

 direction as the long axis of the body and parallel with the 

 spicules. In front they envelop the anterior ends of the 

 spicules, behind they are attached to the wall of the cloaca. 

 This muscle obviously acts as protractor of the spicules. 



A second set of muscles (ibid., rs) passes from the body- 

 wall to the posterior portion of the ductus, to the cloaca, and 

 to the protractor muscle. It consists of a series of muscular 

 bundles lying in the coronal plane of the animal and on the 

 side of the body-wall attached mainly to the lateral lines. 

 By enclosing the posterior portion of the ductus it assists in 

 expelling the sperm ; by the attachment to the protractor it is 

 enabled to act as retractor of the spicules, and by its attach- 

 ment to the cloacal wall as dilator of the cloaca. 



The spicules are curved, pointed at their free ends, "IS mm. 

 long. They consist apparently of a chitinous material, ai'e 

 hollow at their upper portions, containing jDrotoplasm. The 

 accessory piece is triangular, grooved at the sides, the spicules 

 fitting into the grooves. 



Female Reproductive System. 



The female reproductive organs (text-fig. 2) consist, as is 

 usual in Nematodes of two tubes, uniting before reaching the 

 external aperture. The tubes do not lie side by side, but one 

 is found in front of, the other behind, the external aperture. 

 This aperture is situated in the middle of the mid-ventral 

 line of the body, the entire gonads being included in the 

 middle two quarters of the body. 



Each tube consists of ovarian region (text-fig. 2, ov. v.), 

 including an ovarian coecum [ov.c), uterus (w^.), and vagina. 

 The ovarian csecum lies furthest from the external aperture, 

 the rest of the ovarian region being bent back on the oviduct. 



