238 Gllruth, Stveet, and Dodd : 



stages of the same species of parasite, as one misrht assume, is 

 at least questionable since the larger forms are markedly less 

 differentiated in character than the smaller forms. That they 

 are not due to differences in method of fixing or staining is 

 evident from the frequency with which the two dissimilar forms 

 are met on the same slide, and even almost alongside each 

 other. Further, many of the smears were made from blood or 

 organs containing living larvae. These different forms were 

 met with in all the smears. No. 2 being much the least frequent. 



No. 1. — Elongated and cylindrical, with a bluntly rounded 

 head end, and a bluntly tapered tail. Generally 98 fx long by 

 4. 5 /x, wide, i.e., rather less than a red blood corpuscle in 

 diameter. The head is hyaline for 5.6 /x long, showing only 2 

 nuclei on one surface, deeply staining blue with Giemsa, and 

 behind this a row of large, clearer, more homogeneous nuclei 

 faintly stained pink. The bulk of the body is ocupied by a 

 series of deeply staining (blue) nuclei which appear to form 

 the periphery of the cellular body, and to enclose a longi- 

 tudinal series of pink-stained nuclei similar to those described 

 above, though rather smaller, presumably the future alimentary 

 canal. At the point marked 2 in Fig. 1. these or rather 

 larger similar nuclei form a group of cells. The embryonic 

 sheath was not visible, but the clear colourless ext-ernal body- 

 wall can be seen sometimes to show minute transverse striations 

 such as those described by Manson in Filaria hancrofti. var. 

 nocturna (Manson, p. 550). 



Tlie clear spot, Manson's '" V-spot," found near the head end 

 in some other filarial larvae, does not appear to be present as 

 such here. At the points marked (4) and (5) two small irregular 

 '■ breaks " in the line of nuclei can be seen. At the point 

 marked (1), l-7th of the length of the body from the tail end, 

 tlie well-marked "' tail-spot " is visible, while at (3) a sharply 

 defined diamond-shaped clear area is visible which does not 

 seem to be represented in exactly the same place in other filarial 

 larvae. It is 5 /x long. 



No. 2. — This is the least frequent of the 3 types, and shows 

 a much sharper and less hyaline head. The body generally is a 

 very faint blue with less deeply stained, more pinkish nuclei 

 than in No. 2. Rarely the " pink nuclei " (which are much less 



