On a new Sporozoen from the vesiculas seminales of Pericbaeta. 787 



of the uuencysted parasite would be unuecessary, were it mercly 

 desired to' show its specific distinctness from any knowu form. 



Besides the young stages described above which are of about the 

 same size as M. lumbrici, I met with a number of individuals inter- 

 mcdiate bctweeu these and the eiicysted form. 



I have already pointed out one intermediate stage between the 

 eiicysted parasite and the young individuals. It appears however to 

 be rarely the case that the parasite becomes encysted before attaiuiog 

 to greater dimensious than the specimeu illustrated in fig. 9. 



In the body cavity, particularly in the posterior region, were 

 numerous Gregarines of which examples are illustrated in figs. 10, 12, 13. 

 I also found individuals belonging to this stage in the vesicula seminalis; 

 they agree in their geueral form both with the very young specimens 

 and with the encysted individuals; in ray opinion they are undoubtedly 

 tlie mature unencysted stage. 



The granules Alling the body were sometimes confined to the central 

 region, and sometimes extended into one or both of the processes. The 

 granules (figs. 5, 6) were ideutical in character with those of the en- 

 cysted form being much larger than those of the young specimens. 



In those cases in which the granules of the eutoplasm do not 

 extend into the processes of the Gregarine their contents consists 

 of finely granulär protoplasm ; this is continuous with a layer of finely 

 granulär protoplasm of excessive thinness which surrounds the coarsely 

 granulär entoplasm of the central region of the body. This finely 

 granulär layer is probably to be looked upon as the ectoplasm. Even 

 when the large granules of the entoplasm do extend into the processes 

 of the body, they form but a narrow layer, the ectoplasm being re- 

 latively of great thickness. It seems to be very possible that the 

 movements of the body, if there are any in the living Gregarine, are 

 brought about by the contractions of the granulär ectoplasm; if so its 

 extreme thickness^ in the two processes of the body would seem to 

 indicate that these are more especially organs of locomotion. In Cono- 

 rhynchus (Greeff, 8) the body is furnished with numerous processes 

 which are chiefly composed of ectoplasm. These facts still further 

 favour the supposition that tlie form of the spirit preserved examples 

 of this Gregarine^is that of the living form. 



The cuticlewas proportionately thicker than in the early stages. On 

 the two processes of the body (figs. 11, 12) were a series of rather coarse 

 striatious runniag in a direction transverse to that of the long axis of 

 the Gregarine at an angle of about 45", These were not visible in 



