On Flagellated Protozoa, dte. By Edgar M. Orookshank. 917 



The first glance at the parasites recalled the appearance of 

 nematode haernatozoa, as if, indeed, they might be embryo Filarise, 

 but when I had carefully studied several specimens, and had 

 further undergone the searching examination entailed by the 

 accurate focusing necessary to obtain a number of sharply-defined 

 photomicrographs, I came to the following conclusions : — 



The somewhat tapering central portion, or body, of the parasite 

 is continuous at one end with a whip-like lash, and at the other 

 end terminates in an acutely-pointed stiff filament or spine-like 

 process. Here and there, possibly from injury or want of 

 development, the spine-like process appears to be blunted or absent 

 (Photo 7). By very careful focusing on the upper edge of the 

 central portion, I discovered the existence, much more markedly 

 in some of the parasites than in others, of a longitudinal mem- 

 brane with either a straight or undulating margin (Photos 4, 5, 

 6, and fig. 193). The membrane is attached along the body, arising 

 from the base of the rigid filament, and becomes directly continuous 

 at the opposite end with the flagellum. In some cases the edge 

 only is deeply stained, giving the appearance of a thread con- 

 tinuous with the flagellum, so that one might be easily led to 

 overlook the membrane, and imagine that the flagellum arose 

 from the opposite end of the body, at the base of the spine-like 

 process. 



Close to the base of the spine-like process a clear unstained 

 spot is, in many parasites, easily distinguished (Photos 1, 2, 3), 

 and at the opposite end there is, in some, the appearance of the 

 deeply-stained protoplasmic contents having contracted within the 

 faintly stained membranous investment. Where the longitudinal 

 membrane has a wavy outline the undulations are much more 

 marked in some cases than in others. Here and there the wavy 

 outline appears first on the one side of the central portion, and 

 then on the other, but there never is any waving outline on both 

 sides of the same part of the body, and this was explained by careful 

 examination, which showed that in dying the somewhat ribbon-like 

 parasite had become doubled on itself (Photo 9). The discovery 

 of this undulating membrane at once suggested to my mind an 

 explanation of the lateral pseudopodia described by Evans. If we 

 imagine that we are looking down upon the parasite, with the edge 

 of the membrane towards us, one can conceive that the rapid undu- 

 lations first on one side and then on another, might give an image 

 upon the retina which could be construed as due to the protru- 

 sion of lateral pseudopodia. I may add that I could not discover 

 in the stained preparations any trace of the circlet of pseudopods, 

 and I think the undulating membrane may account for this 

 appearance also. 



Owing to the somewhat curved and twisted shape of the 



