164 GENERAL HISTORY OF THE INFUSORIA. 



as before conjectured, end in disintegration and death. But all this, as I have 

 just stated, can only be determined by following the development of the spore 

 from the commencement. One fact I might add, however, viz. that the robust 

 forms of good size have the power of mthdi-awing theii' cilia and protruding 

 them again ; this happens when they are transferred, from the vessel in which 

 they may be contained, to the slide for examination : many may just at this 

 time be seen to be motionless, ^vith the channels for the cilia empty ; but 

 gradually the cilia are protruded through them, and as gradually the Eudo- 

 rina evinces increasing power of motion, until they are fully protruded, and 

 it SAvims away. 



'' Chlamydococcus undergoes the same kind of changes in development as 

 Eudorina, from which it only differs in structm^e in being smaller, and glo- 

 bular instead of ovoid, in the absence of an external envelope, and in the cilia 

 of the daughter- cells being included within the parent- cell ; hence it also 

 differs in being motionless, though the compartments of the daughter- cells 

 are sufficiently large for them to turn round and move their cilia freely 

 therein, which they are continually doing. The primaiy cell of Cldamydo- 

 coccus, like that of Eudorina, divides up into 2, 4, 8, or 16 cells, and those of 

 the eight- and sixteen- divisions again into groups of 16 or 32 each, so as to 

 resemble the third stage of Eudorina. Hence we may perhaps infer that its 

 fecundating process is similar to that of Eudorina ; but this remains to be 

 discovered. Chlamydococcus has also a great tendency to stop at the two- 

 and four- division, from which it may pass into the ' still ' or Protococcus-ioYm.^ 

 and, floating on the water in a kind of cnist, present cells of all kinds of sizes 

 undergoing ' still ' division. In all its multiplications, partial and entire, 

 however, it generally maintains its primary or spherical form, and does not 

 become ovoid or oblong, like the groups of Eudorina, the only exceptions 

 being in the two- and foui'-division, w^here the green cells are sometimes 

 ovate (probably from want of room in the parent capsule), as represented by 

 Ehrenberg in C. Pulvisculus, — to which I should refer it, had he not also 

 given an ovate form to the type-cell of this species ; nor can I refer it to C. 

 pluvialis, for in all the changes I have yet seen it undergo, the red colour has 

 not increased beyond the minute eye-spot, while this also disappears, and the 

 cilia too, when this species passes into the ' still ' form. Here it undergoes 

 the same kind of division that it does in the active state ; but the parent- 

 cell, instead of becoming distended by imbibition, remains closely attached to 

 the daughter-cells, so as to give the group a mulberiy shape. How long it 

 remains in the ' still ' form I am ignorant ; but having only seen it in the 

 a<itive state dui^ing the months of May, June, and August, and thi^oughout the 

 rest of the year in the ' still ' one, I am inclined to think that it only comes 

 into the active state during the summer months, and then for the purpose of 

 fecundation. 



" In several instances, also, where I have found this Chlamydococcus with 

 Eudorina, they have been accompanied by long Closteriform cells. It was 

 the case in that above mentioned, where the latter was imdergoing impreg- 

 nation. Some of these have an eye-spot, which, with the nature, arrange- 

 ment, and general aspect of their internal contents, show that they belong to 

 the class of organisms with which they are associated. Their cell- wall also 

 is more or less plastic, or was so when they were assuming this spicular form ; 

 for many have one or more diverticula extending from them, some are bifid, 

 and a few irregularly steUate. What they are I know not ; but Dr. Cohn 

 has figured the same kind of cells, in company with SphoiropJea anmdina, 

 under impregnation." 



StephanoaphaTa. — To Dr. Ferdinand Cohn, to whom science is so deeply 



