HOOKWORM. 



243 



of the worm terminates in a buccal bursse, which contains the 

 oval papilhe above, the chitinous capsule and ventral lancet 

 ventral] y, the lateral lan- 

 cet to the side, and, most FIG. 94. 

 important, the single con- 

 ical tooth dorsal! y. This _ ^^^MFM&i^-jt. 



FIG. 93. 



FIG. 91. FIG. 92. 



FIG. 91. New World male hookworm. Natural size (Stiles). 



FIG. 92. New World female hookworm. Natural size (Stiles). 



FIG. 93. The same, enlarged to show the position of the anus (a) and the vulva 

 (r) : in, month (Stiles). 



I-'IG. '.!. Dorsal view of anterior end of New World hookworm: b. c., Buccal cav- 

 ity; c. v., cervical papillae: d. in. (., dorsal median tooth, projecting prominently into 

 the Imreal cavity: <l. .<///. /., small dorsal semilunar lip; e., oesophagus : m. m., mar- 

 gin of mouth, the prominent oval opening seen upon high focus: p.p., papillae; 

 v.sm. L, large ventral semilunar lips homologous with the ventral hooks ofA.duo- 

 <lni(itr. Greatly enlarged. (Stiles.) 



distinguishes Necator americanus from the Old World hook- 

 worm, Ankylostoma duodenale, in which there are four teeth. 

 The necator is almost cylindrical in shape, and tapers in the 



