SPIROCHATA BALBIANII AND SPIROCHATA ANODONTA. 27 
from macerated specimens. I have not met with macerated 
specimens myself on which I should care to base any very 
definite inferences, for in macerated preparations the fibrils 
might equally well be those of the membrane. However, in 
addition to what has been stated in the preceding, we have 
better evidence, I think, from stained normal specimens that 
contractile fibrils do occur in the periplast, although they are 
invisible in fresh specimens, and are only seen in some 
favourably stained preparations, and they are probably com- 
parable to the myonemes of the ectoplasm of Trypanosomes, 
seen best in Piscine forms (e.g. Trypanosoma raje). 
In the favourably stained specimens of 8. balbianii here 
referred to, which had been treated with gentian-violet or 
iron-hematoxylin, longitudinal lines or ridges could be seen 
near the outer edge of the periplast (PI. 1, figs. 2, 11, my.), 
running nearly parallel to the contour of the body, and better 
seen in some parts of the organism than others. ‘hese lines 
were quite distinct from the membrane or any part or fold of 
it (see fig. 2, where the chromatic border of the membrane is 
evident and quite separate). These are, I think, myoneme 
fibrils, staining rather deeply violet with gentiandye. Similar 
appearances may be seen in other preparations. 
There are, undoubtedly, myoneme fibrils also present in 
the membrane, which is an extension of the periplast. 
The periplast is, then, hyaline, and consists of viscid proto- 
plasm of a firm texture, which gives a definite contour to the 
body, and yet is itself flexible. The periplast is directly con- 
tinued into a laterally extended, spirally arranged, “ undu- 
lating”? membrane. I would prefer to deal with the membrane 
separately, but at this point it is convenient to consider a 
recent note by Swellengrebel (10). Herein the membrane of 
a Spirochete is considered to consist of two distinct parts: 
(1) a periplastic appendix, and (11) a chromatic band or ribbon 
running along the cell, following the appendix, and some- 
times beginning in a granule (“ centrosome,” Pl. 3, fig. 22; 
also Pl. 1, fig. 5a). 
Regarding these remarks of Swellengrebel, it seems to me 
