RHODO-THIOBACTERIA 159 



which is characteristic of Thioporphyra voliitans, for as far as 

 can be ascertained the bud is formed entirely from the material 

 in this differentiated region. 



(2j A protuberance appears opposite the clear space (Fig. 

 35^), and a bud emerges which is devoid of a definite membrane, 

 and which is irregularly contoured. It was not possible to 

 ascertain whether the membrane burst to admit of the pro- 

 trusion of the bud, or whether the bud was abstricted. Usually 

 at this stage it contains one sulphur globule. 



(3) Beyond this point the development does not follow a 

 uniform course. It may continue its growth but remain in 

 attachment to the parent cell, in which case a bud is not formed 

 but a unicoccus becomes a diplococcus, and a diplococcus a 

 tricoccus. Or the bud may separate early from the parent, 

 in which case the growth medium is occupied by a mass of 

 small non-motile globules, each containing a sulphur globule 

 (Fig. 35 d and e). The cells formed by budding are of uniform 

 size and shape within certain limits. 



In addition to the above, structures have been found in 

 Thioporphyra vohUans which may be endospores similar to 

 those formed in the genus Bacillus, but no opportunities have 

 occurred to study them more closely (Fig. zy)- 



ClLIATION AND MOVEMENT. 



The movement is one of rapid translation and rotation, 

 by a long single cilium. 



The pleomorphism of this organism has been considered 

 in Chap. I., and the intimate structure of the cell will be dis- 

 cussed in Chap. X. 



