STUDIES OX THE ECTOPAEASITIC TREMATODES OF JAPAN. J[) 



ohvionslv ,g-:ii]g-li()nic cells ran not bo observed ; but in Mici-ocoinU' 

 srhastis there are two ]^airs of laro'e polygonal cells in the ventro- 

 lateral portir-n of a cross-section passing through the anterior ])ai-t of 

 tlie brain, which are jTovided with very large, vesicular nuclei with a 

 distinct membrane and coiitaining each a single, large nucleolus and 

 numerous, weakly stained granules ({rrobably cViromatin). The proto- 

 ])lasm is hnelv granular and has no external membrane, so that the 

 cell-l)odv beeomes gradually fainter towards the periphery (PL R , 

 Ö), In J. vine hetcroccrca (PI. VIII. fig. 2) also, there are some 

 cells of tliis; kind of various sizes in the same region .of the body. 

 In Didiihphora ^ri^^ilk (PL XI, figs. 1 & 2) the brain itself is entirely 

 ÏVQQ from cells of all soi-ts ; but at the root of the posterior nerves, 

 there are numerous cells of polygonal f)rin with finely granidar. 

 well-staining protoplasm, and with a nufleus containing one or more 

 nucleoli. These are undoubtedly nerve cells. Besides these, how- 

 ever, there are in this species two pairs of gigantic cells in that part 

 of the Ixxlv which corresponds to Avhere the large cells already 

 mentioned are found in IMicrocotulc sehaslis. They are pcdygonal in 

 form, and the large vesicular nucleus, which contains, besides a single 

 large nucleolus, numerous small granules, is siuTounded by a very 

 finelv graiudar, well-staining protoplasm Avhich is totally destitute ot an 

 external mend)rane. Sometimes the protoplasm has seemed to be 

 drawn out into a faint process, and fibres to be given out from the peri- 

 phery of the nucleus (PL XI, fig. 1. left side). I have described similar 

 cells in similar positions in Diplozoon^^; and t have no doubt that they 

 as well as tho.se of Mlcyocotijle and Axinc are ganglionic cells. 



In TristoiiJinii. there are numerous o-anglionic cells within the 

 brain as well as in the main nerves. The greater number of them are 



1). /. c. p. 171, and fig. 25. 



