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XL] nematodes, 3-4 in. in length (Fig. 110). The sexes live together, often inextricably coiled about each other. Sometimes they are enclosed, coiled up several in a bunch and tightly packed, in little cyst-like dilatations of the distal lymphatics (Maitland); sometimes they lie more loosely in lymphatic varices; sometimes they inhabit the larger lymphatic trunks between the glands, the glands themselves, and, probably not infrequently, the thoracic duct.

The female filaria is the larger, both as regards length and

Fig. 110.—F. bancrofti (natural size): a, male; b, female.

thickness. It measures 85-90 mm. in length by 0·24-0·28 mm. in breadth. The two uterine tubes, occupying the greater extent of her body, are filled with ova at various stages of development. In both sexes the oral end, armed with a double row (number uncertain) of exceedingly minute papillæ (Fig. 111, b), is slightly tapered, club-shaped and simple; the tail (Fig. 111, a, c) also is tapered to comparatively small dimensions, its tip being rounded off abruptly. The vagina opens



on the ventral surface about 1·2-1·3 mm. from the anterior extremity; the anus just in advance of the tip of the tail. The cuticle is smooth and without markings.

To the naked eye the male worm is characterized by its slender dimensions (about 40 mm. in length by 0·1 mm. in diameter), by its marked disposition to curl, and by the peculiar vine-tendril-like tail, the extreme end of which is sharply incurvated (Fig. 110, a). The cloaca gives exit to two slender, unequal spicules (0·2 and 0·6 mm. respectively). The existence