NEC A TOR 



673 



the bursa is bilobed. In the female the vulva lies in the anterior 

 part of the body. 



Type Species. — -Necator amevicanus Stiles, 1902. Other species: 

 A^. africanus Looss, 191 1, in the chimpanzee. 



Necator americanus Stiles, 1902. 



Synonyms. — Dochntius duodenalis R. Leuckart, pro parte; Unci- 

 naria americana Stiles, 1902 ; AncylostoMaamericanuM von Linstow, 

 1903, pro parte. 



In 1902 Stiles discovered that two distinct genera were being 

 confused under the term Ancylostoma, and eventually called the 

 new genus Necator. Leiper has recently shown that this new genus 

 is very widely distributed over the world, and is the common cause 

 of ankylostomiasis in Ceylon; while it occurs in India, Assam, 



Fig. 302. — The Fig. 303. — The Bursa Copulatrix of a Male 

 Mouth Capsule Necator americanus Stiles. 



OF Necator ameri' Spicules; 2, costa ventralis; 3, costa lateralis pes- 



canus Stiles. terior; 4, costa lateralis externa et costa lateralis media; 

 (After Looss, 5, costa dorsalis externa-; 6, costa dorsalis; 7, dorsal 

 from Mense.) lobe; 8, lateral lobe; 9, ventral lobe. 



(After Stiles.) 



Burma, the Philippine Islands, Fiji, Japan, America, and has been 

 found in West and Central Africa and in North-West Rhodesia. 

 In due course, no doubt, it will be reported in other places. 



Morphology. — The body is cylindrical, and somewhat attenuated 

 anteriorly. Head acutely bent dorsally. Mouth with a ventral 

 pair of prominent semilunar chitinous plates and a dorsal pair of 

 slightly developed plates. Into the floor of the mouth projects the 

 opening of the dorsal head gland, which appears like a dorsal conical 

 tooth, while deep in the cavity appear one pair of dorsal and one 

 pair of ventral submedian lancets. Excretory pore 0-5 millimetre 

 behind the mouth, with cervical papillae on either side. 



Male 7 to 9 millimetres in length and 0-3 to 0-35 miUimetre in 

 breadth. The bursa consists of two large lateral lobes joined to a 

 dorsal median lobe, which appears as if divided into two, and to 



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