30 H. B. FANTHAM. 
The structure of the membrane herein described is borne 
out by an examination of transverse sections of an infected 
crystalline style, as shown in text-fig. 6, and proves it to be 
an outgrowth of the periplast. 
It has been suggested by Laveran and Mesnil (5) that 
this structure is not really a membrane, but a_ sheath 
(“oaine”’) surrounding the organism, and only attached at 
the extremities, In their monograph on Trypanosomes 
Laveran and Mesnil thus set forth their views on this struc- 
ture:—‘“‘Une gaine lache unie au corps a ses deux 
memobr. 
‘ 
' 
' 
' 
Me 
f Ve 
ertplast chr. masses 
ReCUP 
a 6 c 
Trxt-F1c. 6.—Diagrams of transverse sections of Spirochetes as 
seen on sectionising an infected Lamellibranch crystalline style. 
The membrane is a lateral extension of the periplast containing myo- 
nemes (my.) and spirally wound. ce passes approximately through a 
node of the membrane and shows the thickened chromatic border. 
extrémités et dans laquelle ce corps flotte; en tout cas, 
il n’y a pas de bordure épaissie comme a la membrane 
ondulante des Trypanosomes.’ This question is a most 
difficult one, and is certainly not to be passed over lightly 
by mere dogmatic assertion either one way or the other. 
However, one can see in preparations the spiral arrangement 
of the membrane in most cases and the actual crossing over 
the body from one side to the other, both above and below 
(Pl. 3, fig. 22; Pl. 2, fig. 29), and, furthermore, the organism 
possesses a distinct spiral motion, evidently guided by the 
spiral arrangement of the membrane. Again, if the body 
moved more or less freely inside a sheath one might expect 
