It appears to me not improbable that this specimen may be found to supply what has hitherto been a missing link, namely, the male animal. Since writing this I have had the opportunity of submitting the specimen to Dr. Munson, who at once recognised it as the male worm, and has undertaken to make a careful microscopical examination and description of it. “_Report by DR. MANSON on the structure of the_ Filaria loa, _from an examination of the specimen removed in the foregoing case, as well as of the specimen of the same parasite exhibited at a meeting of the Society on January 31st, 1895. The latter filaria was removed from the eyelid of a patient by Dr. J. R. Logan, Liverpool._— [Illustration: FIG. 1. Male. Nat. size.] [Illustration: FIG. 2. Male. × 6.] [Illustration: FIG. 3. Head of male.] [Illustration: FIG. 4. Tail of male. Dr. Logan’s.] [Illustration: FIG. 5. Tail of male. Dr. A. Robertson’s.] _Filaria loa: male._—Body filiform, cylindrical, measuring from 25 mm. to 30 mm. in length, by 0·30 mm. in breadth, of uniform thickness, except where it tapers at the head and tail. The cephalic end tapers somewhat abruptly to the simple mouth, which is destitute of papillæ and armature. There is no distinctly marked neck, but there is a sort of shoulder about 0·15 mm. behind the mouth, where a number of strong muscular longitudinal bands originate to pass down the body. In one of the specimens the extreme head end is retracted and abruptly truncated, measuring at the free end 0·1 mm. across; in the other worm this part is more conical, and in it a short pharynx can be seen, which opens out somewhat posteriorly. At 0·1 mm. from the mouth the diameter of the worms is 0·15 mm.; further back, at 0·6 mm. from the month, it is 0·25 mm. The tail end is sharply incurvated and, perhaps, excavated ventrally; it is not spirally twisted. The tail is provided with well-marked lateral alæ, which can be traced forwards to a point 0·3 mm. from the tip of the tail. At the base of the anterior papilla the tail is 0·08 mm. in diameter. There are five well-marked papillæ on each side of the ventral surface of the tail. The three anterior papillæ are præanal and very large, the most anterior being the largest. The papillæ are closely approximated, stout, and bulbous at the free end; they measure 0·04 mm. in length by 0·022 mm. in breadth. The fourth papilla appears to be adanal or post-anal, and is rather more separated from the third than the three anterior papillæ are from each other, and is distinctly nearer the middle line; it is also considerably smaller, 0·03 mm. by 0·01 mm. The fifth and most posterior papilla is very much smaller than the others and differently shaped, being conical and sharp-pointed. It measures 0·014 mm. in length by 0·005 mm. in breadth at this