526 0. CLIFFORD DODELL. 



ill the middle of the incurved individual, at a point where a 

 transverse partition separates two adjacent protoplasmic 

 chambers from one another (cf. fig. 4). The partially 

 divided organism then untwists itself — passing out of the 

 condition of incui-vation to the original form of a simple 

 spiral (fig. 6). In this condition fission is completed, and the 

 two daughter-individuals separate from one another. The 

 latter are, of course, short individuals in the form of spii-als 

 consisting of two or three turns. 



In the division of the body the crista is also involved. It 

 divides with the rest of the body, in the manner shown in 

 fig. 7. This figure shows the middle region of a dividing 

 Cristispira which is just straightening itself after being in 

 the state of incurvation. 



The whole process of division is extremely simple, and 

 resembles — apart from the incurvation — the process of divi- 

 sion which can be seen in many Spirilla and other 

 Bacteria. 



I think there can be no doubt at all that the incurved 

 individuals are not really stages in a longitudinal division — 

 as they seem frequently to have been interpreted by other 

 workers. The crista does not split longitudinally. I have 

 never seen partially longitudinally split individuals ; the 

 transverse division of the looped end of the incurved organism 

 is often very easily seen; the number of turns in the spiral 

 in a newly divided individual is half that of the undivided 

 individual; and finally, the width of all individuals — when 

 allowance is made for the differences due to technique (see 

 p. 515) — is fairly constant. These facts indicate most clearly 

 that division is transverse and not longitudinal, as Schellack 

 and Gross have maintained in the case of other species of 

 Cristispira. I believe, with these two observers, that all 

 cases of longitudinal division which have been described in 

 Cristispira are due to misinterpretation of the observed 

 appearances. 



Formation of gametes, conjugation and encystation I have 

 never encountered. These phenomena — first described by 



