14 PROCEEDINGS OF THE ACADEMY OF [Jan., 



itself, although, assuming Schewiakoff to be incorrect, there was 

 no other conclusion possible. The existence of locomotor organs, 

 such as small cilia or temporary protoplasmic processes, was next 

 considered. There was not, however, the slightest evidence for such 

 organs to be detected with living gregarines, and the most rigid 

 staining methods gave wholly negative results. Varying the obser- 

 vational conditions was next tried. I had been making my studies 

 after the methods which I suppose have been generally employed in 

 work on li\'ing gregarines. The highest powers used were those 

 obtained with a one-eighth-inch dry lens and a No. 4 eye-piece. I 

 had also followed the instinctive tendency to focus on the periphery 

 of the gregarines, which results in studying no more than an optical 

 section of the animals. 



Knomng that Stenophor a juK has the longitudinal elevations of 

 the cuticle well developed, it occurred to me that they might furnish 

 a means of getting at additional data. Accordingly, I began to 

 make observations on the upper surface of the gregarines, using a 

 one-twelfth-inch oil-immersion lens. It developed at once that this 

 could not be done with ordinary illumination, on account of the 

 opacity of most gregarines. But with the use of a lamp, it was 

 easy to get an illumination sufficiently intense to render the grega- 

 rines almost transparent. The light was permitted to pass from 

 the mirror to the sub-stage condenser without the interposition of 

 blue or ground glass, and the diaphragm Avas left well open. The 

 difficvdty of managing a wet mount when studied under an oil- 

 immersion lens was obviated in some cases by gluing the cover-glass 

 to the slide with vaseline or spermaceti. This is not always neces- 

 sary, for frequently the surface tension of the fluid of the mount 

 will hold the cover-glass perfectly rigid. 



This method very quickly revealed the fact that gregarines show a 

 movement which hitherto appears to have escaped observation. 

 This I shall designate as the transverse movement. It may be seen 

 to take place when gregarines are behaving in any of the ways 

 already described. It manifests itself as a shifting of the cuticular 

 striations in a direction at right angles to the long axis of the ani- 

 mal. The more superficial granules of the endoplasm also take part 

 in it, which indicates that the myocyte, or muscular layer, is in- 

 volved. There is often to be seen in contracting gregarines a flow of 

 granules which calls to mind the flow of granules seen in an amoeba. 



