256 



HOOKWORMS 



World species the mouth (Fig. 101 A) is armed with a number of 

 chitinous hooklike teeth, which in the American species are 

 replaced by hard ridges or lips (Fig. 101B). The male worms are 



u 



Old World hookworm 



FIG. 100. American hookworm, Necator americanus, male ( $ ) and female ( 9 ) ; 

 b.c., buccal cavity; ph., pharynx; int., intestine; cerv. gl., cervical gland; t., 

 testis; sp. d., sperm duct; b., bursa; ov., ovaries and oviducts; v., vulva or 

 genital opening; a, anus. X 8. (Partly after Manson.) 



also cylindrical but instead of tapering at the tail end they possess 

 an umbrella-like expansion known as a bursa, which is sup- 



FIG. 101. Buccal cavity and mouth of Old World hookworm (A), and American 

 hookworm (B), showing teeth in former and cutting ridges in latter. A, X 100; 

 B, X 230. (After Looss.) 



ported by clawlike rays somewhat suggestive of the ribs of an 

 umbrella (Fig. 102). The bursa is used for holding the female 

 during copulation. It was the clawlike ribs of this " umbrella " 



