STUDIl!:S ON CEYLON IL-EMATOZOA. 755 



are met with in this situation have a round or oval nucleus 

 with the chromatin grains fairly regulai'ly arranged (figs. 

 28-84), and seem, as far as morphological features are con- 

 cerned, to be the motile phases of such types as are shown in 

 figs. 1-3 and 9a from the blood of the Nicoria, and figs. 

 21 and 26 from the crop. The protoplasm of the hsemo- 

 gregarines have very little affinity for most stains, and this 

 is particularly true of the stages in the leech. 



The motile creatures carry out movements of flexion and 

 also of contraction and extension; in addition to this they 

 can glide by means of very shallow undulations passing down 

 the body. This constricting motion, as in analysis it really 

 is, is most strikingly ^een in H. leschenaultii (a hfemo- 

 gregarine from H em idacty 1 ns leschenaultii), but the 

 difference is purely one of degree. 



The faculty of contracting and extending the whole body 

 shown by the motile forms of H. nicorias is a disturbing 

 factor when an attempt is being made to divide the parasites 

 into different categories. After much searching, I have 

 come to the conclusion that the only distinction between the 

 parasites while still in the lumen is one of size, and I 

 consider this to have practically no value when O'ae remembers 

 the capacity of the creature for stretching, and the great 

 difficulty in getting a correct idea of bulk in an animal of 

 this type. The drawings have been made from sections, and 

 here one has the additional danger of not always getting the 

 animal in a perfectly horizontal position. 



It was noticed not infrequently in the live specimens from 

 the intestine that two equal individuals ranged themselves 

 side by side, but complete fusion was never observed. In the 

 sections this association in couples was again found (see 

 fig. 35), and the individuals showed no differentiation. Here, 

 also, stages indicating complete fusion were not seen ; only 

 the two cases figured (figs. 36 and 37) were observed, and 

 as both these are cut obliquely they are not particularly 

 convincing. I therefore think that if appearances such as 

 those shown in figs. 35-37 relate to conjugation at all, they 



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