266 



THE ROUND WORMS 



anterior end of the worm projects to pour forth its striated embryos 

 upon contact with water. 



The mouth is terminal and the body uniformly cylindrical. The uterus is a con- 

 tinuous tube filled with sharp-tailed, transversely striated embryos, 650X17^, and 

 constitutes the greater part of the body, the alimentary canal being pressed to one 

 side. The genital organs probably discharge through the oesophagus. The body 

 when being extracted is rather transparent. The tip of the tail is bent, forming a 

 sort of anchoring hook. Recently Leiper fed monkeys on bananas containing in- 



7-08. 



FIG. 72. Round worms (Filariidae). i. Hooked posterior extremity and ante- 

 rior extremity of Dracunculus medinensis; 2, cross section of uterus filled with embryos, 

 D. medinensis; 3 and 4, free embryo and embryos of D. medinensis in intermediate 

 host (Cyclops); 5, natural size of female Filaria bancrofti; 6, embryo of F. bancrofti 

 in blood; 1 7, tail of male F. bancrofti; 8, male and female of F. loa (natural size); 

 9, tuberculated integument and posterior end of male F. loa; 10, posterior end of male 

 F. perstans; n, male of F. bancrofti (natural size); 12, blunt-tailed embryo of F. per- 

 stans; 13, sharp-tailed embryo of F. demarquayi. 



fected Cyclops, and at the autopsy six months later obtained both male and female 

 forms. 



As regards the life history, Fedschenko, in 1870, showed that the embryos when 

 liberated swam around in water and finally entered the bodies of species of the genus 

 Cyclops. The female tends to come to the surface in the lower extremities, and 

 experiments show that if on the blister-like points of emergence some water be 

 squeezed out from a sponge, the uterus will eject a milky-looking fluid containing 



