42 H. B. FANTHAM. 
of the nucleus—which probably exists in other organisms 
showing morphological characters between Spirocheetes and 
the undoubted Protozoa, and which have yet to be examined. 
Similar remarks apply to the use of the word ‘ chromo- 
somes” for the chromatin masses occurring along the spiral 
filament, and the use of which term by Perrin has been pre- 
viously referred to. } 
I have not seen definite evidence of reducing division of 
the chromatin in these organisms. 
DIvIsIoNn. 
The method of division in Spirocheetes is much disputed, 
some authorities, as Laveran and Mesnil (5), maintaining that 
it is transverse as in Bacteria generally, while others, as 
Perrin (9), maintain that it is longitudinal, while Certes (1, 
2) and Lustrac (6), most correctly, I think, find both methods 
taking place. Division usually occurs in the crystalline 
style, especially in the case of S. anodonta, less frequently 
in the gut, but I have seen it there in 8. balbianii, when 
no style was present in the oyster. 
Longitudinal Division. 
The usual method is by longitudinal fission, the two 
daughter individuals resulting from a common parent being 
very thin and sub-equal. 
The division is first apparent in the membrane (PI. 2, figs. 
13 to 16), but this is really preceded by division of the 
“basal granules” at the ends of the periplast.. This feature 
has not been noted before. Each basal granule early divides 
into two in forms preparing for division, and the two 
daughter granules may remain attached in a dumb-bell like 
manner for a time (Pl. 2, fig. 15; Pl. 3, fig. 40). 
I cannot agree with Swellengrebel’s ingenious suggestion 
(10) that the chromatic border of a membrane can be divided 
