Note on ii Gregarine. 409 



of conjug-atiou in these forms. The examination of numerous cysts 

 at different stag-es in development makes it apparent that a conju- 

 gation of the kiud described by Cuenot for Monocystis and which 

 with variations is held to be typical of the Gregarines in general, 

 does not occur. Each eyst, whatever may be its size, at the begin- 

 ning of development is found to contain a single niicleus, the chro- 

 matin of which is aggregated into a central reticular mass (Fig. 8). 

 Before dividing it g-ets rid of the greater part of its chromatic sub- 

 stance and the nucleus loses its staining reaction with ahim-haema- 

 toxylin (Fig. 9) ; it then proceeds to divide and forms a ring of 

 nuclei round the periphery of the cyst (Fig. 10), which at first do 

 not stain with nuclear dyes, but as they go on increasing in number 

 they regain their staining properties. When a complete investment 

 of small nuclei is formed round the cyst, invagination occurs at 

 various points (Fig. 11), and in this manner rings of nuclei are formed 

 within the cyst surrounding islets of residual matter. From these 

 rings the sporozoites are formed (Fig. 1 2), and by the rupture of the 

 cyst are set free in the body cavity of the crab. The sporozoites, 

 while in the cyst, dififer from those that bave been set free in the 

 body cavity in shape and in the form of the nuclear matter 

 (Figs. 13 a and b). 



There is no trace in this history of the occurrence of conjuga- 

 tiou, nor are two nuclei ever found together in one cyst at the 

 beginning of development. It is clear therefore that if conjugation 

 does occur at all in the life history it must take place at some 

 different period to that which is usuai for Gregarines. I have noticed 

 among the sporozoites found free in the body cavity of the crab a 

 fendency to fuse and to form associations (Fig. 13 c) but of any 

 definite process of conjugation at this stage I can obtain no evidence. 



27* 



