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824 buccal capsule are one pair of dorsal and one pair of ventral subniedian lancets. The caudal bursa of the male presents a short dorso- median lobe, which often appears as if it were divided into two lobes. The dorsal ray is divided to its base, its two branches are prominently divergent, and their tips are bipartite instead of tridigitate, as in A. duodenale. The common base of the dorsal and dorso-lateral rays is very short. In the female the vulva is placed slightly in front of the middle of the body. The eggs (Fig. 168, e) are larger than in ankylostomum; they measure 64 to 75 μ. in length by 36 to 40 μ in breadth. N. americanus inhabits the small intestine of man, and so far has not been found in any other part.

The life-history of this worm has not yet been fully investigated; it is probably similar to that of A. duodenale.

Synonym.—Ankylostomum braziliense, Faria, 1910. This parasite has been found by Lane in stools of three prisoners in Mymensing jail in India. A. ceylanicum is a parasite of the civet cat in Ceylon, but according to Leiper it is apparently identical with A. braziliense, a common parasite of dogs and cats in Brazil. It has also been found in an African lion born in the Calcutta Zoo. The males are 5 mm., the females 7 mm. long. There are two pairs of ventral marginal teeth. The bursa of the male has clefts dividing the dorsal from the lateral lobes; the dorsal ray bifurcates, each branch bifurcating again. This species is probably of little importance as a parasite of man.

History.— Although Griesinger had previously shown that Egyptian chlorosis was due to the presence of the ankylostomum in the small intestine, and although similar observations had been made on negroes in America, it was not until the very fatal epidemic of anæmia among the miners in the St. Gothard Tunnel (in 1880) had called the attention of European observers to the subject, that the importance of this parasite as a pathogenic agent began