STUDIES ON CEYLON H.EMATOZOA. 749 



10 and 11).^ The parasite remains inside the blood-corpuscle 

 {fig. 11 is a case where the creature has been liberated 

 ruechanically in the making of the film), and does not undergo 

 any increase in size. Finally, the protoplasm segregates 

 round the small, slightly elongated nuclei, and a correspond- 

 ing number of little falciform merozoites are formed inside 

 the original envelope (figs. 14 and 15). This stage is rather 

 difiicLilt to find and must be of short duration, as it is some- 

 what rare in comparison with the number of multinucleate 

 creatures to be found in the blood. In the cases 1' have 

 found the number of merozoites is six, but I should expect 

 that eight may sometimes be formed, as rare stages with 

 more than six nuclei are to be seen (see fig. 13). Schizogony 

 stages of this type occur in blood from any part of the 

 tortoise. The merozoites, which are much smaller (4^) than 

 those formed in the lung, finally escape and penetrate into 

 another blood-corpuscle, where they proceed to grow. It is 

 unfortunately almost impossible to trace the subsequent 

 career of these young forms with any satisfying measure of 

 certainty. There are, practically speaking, no distinctive 

 featui-es to lay hold of, and once they have increased in size 

 there is nothing to distinguish them from other forms. The 

 impression I have gained in my attempts to follow their 

 development is that they grow into a compact bean-shaped 

 creature of no great size (see figs. 4 and 7). The nucleus is 

 inclined to stain deeply, and is composed of separate granules, 

 which may be arranged irregularly or in a circle — the latter 

 is on the whole the more common. Beyond this point I have 

 not been able to trace these forms; I was always working 

 with natural infections, which appeared to be of a chronic 



^ The question arises as to whether these bean-sliaped forms which 

 give rise to the schizogony in the peripheral blood are derived from the 

 vermiform type. The evidence to Ije drawn from the infections of 

 H. nicorias which I examined is very inconclusive. In H. vittatae, 

 a form parasitic in the tortoise Emyda vittata, however, the recurved 

 type appears only relatively late in the infection, and I am therefore 

 inclined to think it is associated with the later periods of schizogony 

 and possibly with the process as it occurs in the peripheral blood. 



