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XL] 0.240 mm. by 0.0043 to 0.005 mm., Daniels). But along with the blunt-tailed filariæ, and on the same slides, there occurred a sharp-tailed form, also very minute, and resembling mf. demarquaii. Drs. Ozzard and Daniels confirmed this discovery. These observers found that both the sharp-tailed and the blunt- tailed worms behave in fresh blood on the microscope slide much in the same way that mf. perstans and mf. demarquaii do; that is, they wriggle about very actively, at the same time retracting, elongating, and locomoting in the blood. Parental form.— For a time the relationship of these micro-filariæ, both to each other and to mf. demarquaii, remained undetermined. Later Daniels found parental filariæ— male and female— at the post-mortem examinations of two Demerara Indians whose blood, during life, contained both blunt- and sharp-tailed larvæ. The mature worms, apparently numerous, were about 3 in. in length and very slender— about one-half the diameter of F. bancrofti. They were, therefore, not F. magalhdesi (p. 741). The head was somewhat club-shaped and showed no papillae. The tail of the male was much coiled, and carried at least one long protruding spicule. These worms were found in one case in the mesentery and in the fat at the base of the mesentery; in the other " not only in mesentery and abdominal fat, but also in the subpericardial fat." The embryos in utero, Daniels stated, were all blunt-tailed. I had an opportunity of comparing these worms with unquestionable adult F. perstans. I found them to be identical. The peculiar bifid arrangement of the termination of the tail was quite characteristic of that parasite (p. 736). Later, Daniels found at the post-mortem examination of a third aboriginal, in whose blood both the blunt-tailed (F. perstans) and the sharp-tailed microfilariæ had been found (and no others), a few adult F. peratans and, in addition, a female and portion of a male worm of quite a different species— presumably the parental form of the sharp-tailed larvae. The two latter adult worms lay close together, and were believed to have been located in the subperitoneal connective tissues in the anterior abdominal wall. Except in the matter of the caudal extremity, which was slightly bulbous and without cuticular thickening, in size and structure they closely resembled F. bancrofti. Daniels has drawn up a table (p. 741) of the leading dimensions of the three species— F. bancrofti, F.perstans, and of this possibly new filaria for which I propose to retain provisionally the name F. ozzardi.* (Fig. 128.)