SPIROCHEHTA BALBIANII AND SPIROCHEHTA ANODONTH. 409 
Transverse Division. 
This has been stated to occur by Certes (2), Lustrac (6), 
Laveran and Mesnil (5), and Swellengrebel (10). It was 
emphasised as the only method by Laveran and Mesnil, but 
Perrin ingeniously suggested that this was to be explained as 
longitudinally divided forms, separated by 180°, and not yet 
finally disconnected. It seems to me that the determination of 
the number of chromatin masses (“‘ chromosomes” of Perrin) 
might shed light on the matter, and probably settle the point. 
Text-Fic. 11.—Outline of a specimen of S. balbianii vibrating 
about a non-central node. It did not divide. 
_ But these are not always easy to see separately or to count in 
stained preparations. For example, the number of well- 
marked chromatin masses was thirty-eight and forty-three 
respectively in the case of transversely dividing forms men- 
tioned below (see Pl. 3, fig. 19). Some of the thinner bars 
of chromatin may have been added by transverse division of 
previously thicker single ones, but the question of torsion 
must always be borne in mind. 
Personally, I believe that transverse division! does 
occur in addition to longitudinal but less fre- 
quently, for, in the case of S. balbianii, both long 
and short forms are seen. 
1 See Note on page 68. 
