54 H. M. WOODCOCK. 



gametes apparently unite b}^ the pole or point farthest away 

 from the nucleus, and as the fusion becomes complete the two 

 nuclei gradually approach and, nt length, also unite. The 

 nuclear union is quite simple. As in the case of other Gre- 

 garines so far described, there is no sign of a fusion-spindle 

 such as is often met with in the zygotes of Coccidia (Cocci- 

 dium, Adelea, etc.). 



The copulee in fig. 58 were all drawn from sections, in 

 which it is easier to make out the subsequent behaviour of 

 the fusion-nucleus. The chromatin of the two constituents 

 becomes completely intermingled and assumes the form of fine 

 rodlets ; ultimately it appears more granular, the whole nucleus 

 meanwhile contracting and becoming denser. While this is 

 going on, the zygote has surrounded itself with a delicate 

 membrane, and has begun to change its shape, taking on an 

 ovoid form (/). The nucleus has also passed to one end, 

 which we may term the basal end. A section through a 

 cyst full of zygotes (at a rather earlier stage) is drawn in 

 fig. 54. 



Abnormalities. — Before passing on to consider spore- 

 formation, there are one or two abnormal and degenerating 

 appearances to be noticed in the cyst at this time. In fig. 63 a 

 are seen two sporoblasts Avhich have not succeeded in copu- 

 lating. They are considerably shrunken as compared with 

 normal ones, the cytoplasm having lost its granules and 

 become diminished and pale. The nucleus, too, is rather 

 smaller, and stains up almost homogeneously. Two copuloe, 

 which for some reason or other are also unsuccessful, are 

 seen at h. (Possibly, in this case, for lack of better partners, 

 sister-sporoblasts have paired.) They exhibit practically the 

 same structure as the nncopulated ones, only being larger ; 

 in the right-hand one a few reserve granules are still left.^ 

 Fig. 63 c shows an instance of polygamy ; three sporoblasts 

 have evidently copulated, the nuclei of two having already 

 fused. Such cases are not rare ; there are generally a few to 



1 A similar degeneration of certain sporoblasts is described by Cuenot (loc. 

 cit.) in Monocystis. 



