LIFE-CYCLE OF " CYSTOBIA " IRREGULARIS (mINOH.). 51 



similar; in other words, they are completely isogamous. 

 The nuclei certainly do not exhibit the distinctions in chro- 

 matic density, intensity of staining, etc., which Brasil (4) 

 finds in the case of Monocystis, and which, as he points 

 out, are, indeed, apparent both in Cuenot's figs. 22 and 23 

 and in Prowazek's figs. 11 and 13 (loc. cit.). On the 

 other hand, judging from the figures of Siedlecki, Cuenot, 

 and Berndt (loc, cit.) respectively, the gametes in Lankes- 

 teria, Diplocystis, and Gregarina approximate very 

 closely to those of Cystobia in their apparent similarity one 

 with another. 



This perfect agreement (morphologically speaking) between 

 the sporoblasts is best seen in cysts which have been crushed 

 whole on a slide after staining. In sections through a cyst 

 at this stage it frequently happens that either a sporoblast 

 or its nucleus is not bisected, when a casual glance would 

 give the idea of differences in size and nuclear constitution ; 

 such an intei'pretation would be quite false. Primary sporo- 

 blasts are shown in fig. 57 a, h, and c. They are very 

 simple in structure. Each has a definite and fairly constant 

 shape, slightly ovoid to round. The nucleus is spherical and 

 usually situated excentrically. There is no sign of any 

 centrosomic granule in relation with it, such as is figured by 

 Brasil in the case of Urospora. Practically all the chro- 

 matin lies at the periphery of the nucleus in the form of many 

 short rodlets, leaving the nuclear sap free. The cytoplasm 

 is full of round paraglycogen grains ; other granules ai-e not 

 very evident in preparations stained with para-carmine but 

 are numerous in iron-hgematoxyliu ones. 



Conjugation. 



As soon as the sporoblasts are definitely formed and 

 isolated they are ready for conjugation.^ Notwithstanding 



' I have never observed the least appearauce of anything comparable to the 

 chromutic reduction Vi'hich, according to Paehler (29), takes place iu the 

 primary sporoblasts of Gregarina (Clepsydriua) ovata, and which he 

 suggests may indicate bisexual differentiation. The author could not perceive, 



