On a new Sporozoon from the vesiculse seminales of Perichaeta. 789 



Fig. 11 illustnites the taillike process of a Gregarine of this 

 stage highly niagnified to show the cuticle and the Striae; it will be 

 noticed that numerous cells of the perivisceral fluid are adherent to 

 the outside. This I always found to be the case with individuals 

 of this stage. It occurred to mo at first that the tendency of thesc 

 cells to attach themselves to the Gregarine might havc some relation 

 to the formation of the cellular cyst. I do not however think that 

 any particular weight can be attached to the fact that these cells 

 become adherent to the parasite, as the same thing occurs with other 

 foreign bodies in the coelom — for example with detached setse. 



4) Multiplication by fission. 



BüTSCHLi (2, p. 504) reraarks that the propagation of Gregarines 

 invariably take place by spore formation, and that a simple fission of 

 the free parasite never takes place. 



Since Bütschli's account of the Sporozoa was written Rusch- 

 haupt (2) has discovered that fission does occur in the Gregarines 

 of the earthworm. This process cannot however be at all common in 

 the group as it has been so seldom observed. 



In the Gregarine which forms the subject of the present paper 

 I have observed at least two stages of what appears to me to be a 

 process of division by fission. 



So far as this process can be safely interpreted by these two 

 stages it seems to be rather different from cell division in Monocystis, 

 In the latter, according to Ruschiiaupt, a constriction appears in the 

 middle of the Gregarine; the two halves are for a short time connected 

 by a thin bridge which ultimately breaks through. 



In fig. 2 is illustrated what I believe to be an early stage in the 

 process of division. At the extremity of the body a rounded swelling 

 is formed which is fiUed with large granules. I observed a similar con- 

 dition (see fig. 8) in an individual belonging to the youngest stage. 

 In the next stage (fig. 3) the swelling at the extremity of the process 

 has increased so as to be equal in size to the parent form and a 

 process has grown out from the free extremity of this. 



These apj)earances may of course be delusive, but they seem to 

 indicate that a division of the free parasite occurs which is in its 

 nature something between budding and fission. 



I would Interpret the facts as indicating that the formation of 

 new individuals by division takes place as follows. 



