LIFE-CYCLE OF " CYSTOBIA " IBREGULAKIS (mINCH.). 69 



I do not even think that the intertwining lobes and pro- 

 cesses above described are developed in D. niinchinii until 

 nuclear division is well advanced. The very definite and 

 constant position of the nuclei in the gregariniform adults of 

 this species (see figs, 9^ 10^ and 12) is strong evidence that 

 the "body'^ of each associate remains (except in the plane of 

 junction) quite as distinct morphologically as it does, for 

 instance, in Clonospora sparsa (see Leger's figs. 3 and 4, 

 PI. 20 [19], or Minchin's fig. 20 [26j). 



Is triple association successful? — The Diplodina 

 triplets drawn in figs. 20 and 28 seemed perfectly healthy, 

 and possessed typical nuclei ; the one drawn in fig. 29, how- 

 ever, has not the customary appearance and looks rather 

 abnormal. This is a large specimen, being '6 mm. by "4 mm., 

 and its nuclei have stained up almost homogeneously, the 

 karyosomes being small and indistinct. The cytoplasm, too, 

 has an altered look, with deeply staining lumps and grains 

 (g), probably of an albuminoid nature, unevenly scattered 

 about; in addition, a few vacuoles {vac.) are present near 

 the margin. This syzygy, in short, appears as if it were 

 already commencing to degenerate. Opinion differs as to 

 whether these triplets are capable of successful sporulation 

 or not; the weight of evidence, where their further develop- 

 ment has been followed, seems to point to their subsequent 

 degeneration.^ The reason for the binary nature of a typical 

 syzygy will be full}- understood when the essential signifi- 

 cance of association has been discussed. 



Probably, in any case, the associates require to be of about 

 equal age and size if the union is to be successful. Berndt 

 (loc. cit.) mentions that if the members of an ordinary 

 syzygy are of considerable difference in size, no true cyst- 



' Benidt (1) states that in Gregariua euueata associations of more than 

 two individuals invariably come to nothing. Cuenot (loc. cit.) instances only 

 very rare cases of triple association in Diplocystis, one of which has 

 apparently produced sporoblasts. Judging from his fig. 47, however, the 

 sporulation would not seem to have been successful, the sporoblasts being 

 extremely minute and scarcely visible, very different from the well-developed 

 layer in the normal cysts figured. 



