458 



THE ANIMAL PARASITES OF MAN 



the mouth, and projects right out into the cavity, and on its summit 

 opens the dorsal cesophageal gland. 



FIG. 335. Necator americanus : lateral view, showing the dorsal ridge per- 

 forated by the duct of the dorsal oesophageal gland, the lateral lancet and ventral 

 lancet and the nerve papillae, x c. 475- (After Looss.) 



The bursa is about as long as broad, but has the lateral lobes 

 strikingly lengthened, giving a trilobed appearance (fig. 336), but as 



in Ancylostojiia duodenale it 

 is closed on the ventral side. 

 The distribution of the rays 

 is best understood from the 

 figure. The genital aperture 

 lies on a marked conical pro- 

 tuberance ; the cement gland 

 is bilobed in transverse section. 

 In the female the opening of 

 the vulva is in front of the 

 middle line, in A. duodenale it 

 is behind. 



The spicules, 0*92 mm. long 

 are hooked at the extremity. 



Eggs more pointed at the 

 poles than those of A. duoden- 

 ale, 64 //, to 7 2 fjb by 36 /A, so that 



FlG. 336. Necator americanus : bursa of male. it may not be possible to dis- 



The rays from right (top) to left are: (i) pos- tinguish single CggS OWingtO 



tenor, (2) postero-external, (3) and (4) median . & 



doubled, z.<?., postero-median and antero-median, individual variations, yet Oil 



(5) antero-cxternal, (6) anterior (cleft), and above comparing a number they can 

 it on left a pre-bursal ray. x c. 120. (After 



Looss.) be distinguished. 



