NEMATODES OP THE GENUS PHYSALOPTERA, iii. 



canal and have a straight course, dorsallj', down the body, extending a little 

 further back than the ventral pair of uteri, to within 5.6 mm. of the posterior 

 extremity. Each uterus folds foi-ward again for a distance of 5 or 6 mm., and 

 terminates, somewhere about the posterior fourth of the body, in the receptaculum 

 seminis, from which the looped and coiled ovary extends backwards. 



Figs. 11-19. Phijsaloptera antarctica var. typica. 



Female genitalia. Variations in arrangement of the parts nearest to the vulva 

 shown in figs. 11-16. (Figs. 11-15, x 10, fig. 16, x 20). 



11. 34 mm. specimen ; 12. 40 mm. specimen: 13. 23 mm. specimen; 14. 25 

 mm. specimen; 15. 34 mm. specimen; 16. 43 mm. specimen; 16a, vulva (x 32); 

 17. Ovaries, oviducts, receptacula, seminis, and terminal portions of the four uteri 

 of a 43 mm. specimen (x 6.3); 18. Ovum in oviduct (x 127); 19. Receptaculum 

 seminis (x 32); ov., ovary; ovi., oviduct; r., reservoir, r.s., receptaculum seminis; 

 t., common trunk; ut., uterus; v., vestibule. 



The regular disposition of the uteri in straight lines, parallel to the length 

 of the body, with very few coils or twists, their forward extension beyond the 

 level of the vulva, and their termination a considerable distance in front of the 

 anus are all characteristic features. The paired arrangement, one pair above and 

 one below the intestine, is also very common, and the tendency to forward 

 growth is usually confined to one pair which can, as a rule, be distinguished. 



