204 FILARIA BANCROFTI [CH. 



in Mauritius, Reunion and Madagascar. In America, it is 

 common in many parts of the West Indies and Brazil, 

 and cases occur in the southern United States up to lati- 

 tude 40 N. 



Description. The adult filariae do not occur in the peripheral 

 blood circulation, but are found in various parts of the lym- 

 phatics. The males and females generally occur together, 

 often coiled about each other. Sometimes several occur 

 together in small cyst-like dilatations of the distal lymphatics ; 

 they are also found in the larger lymphatic vessels and in the 

 glands themselves, and, probably not infrequently, in the 

 thoracic duct. 



The female is a long, hair-like, transparent, motile worm, 

 50-155 mm. in length, and O'i5-O'7i5 mm. in breadth. 

 The two uterine tubes, easily seen through the transparent 

 integument, occupy the greater length of the body, and are 

 filled with ova and embryos at various stages of development. 

 The body is plain, tapering rather abruptly towards the anterior 

 end to form a distinct neck, beyond which is the slightly en- 

 larged rounded oral extremity. The tail is also tapered, but 

 ends rather abruptly. The cuticle is finely striated. At a 

 short distance behind the head a luminous V-shaped spot is 

 visible, that may represent the water- vascular system. The 

 vulva is situated on the ventral surface at a distance of about 

 2-56 mm. from the anterior extremity. The anus opens 

 immediately in front of the tail, o - 13-0*2 8 mm. from the 

 posterior extremity. The worm is ovo- viviparous. The ova 

 measure 25-38 ^ in length by 15 p in breadth. 



The male resembles the female in its general appearance 

 but is somewhat smaller, usually about 70-80 mm. in length 

 by 0*40 mm. in breadth. When living it may further be dis- 

 tinguished from the female by its marked tendency to curl, and 

 also by the shape of the tail, the extremity of which is sharply 

 incur vat ed, often making one or two spirals. The anus is 

 situated 0*11 mm. from the posterior extremity and from its 

 aperture emerge two slender, unequal spicules, respectively 

 0-2 and 0-6 mm. in length. According to Looss there are 

 three pairs of post-anal papillae ; pre-anal papillae seem to be 



