ON DTPLOZOON NIPPONICUM, X. SP. 



171 



Beside the various elements hitherto described, there nre, in the 

 neighborhood of the brain nnd pliarynx, lari^'e cells of a roundish or 

 polyg'oiial outline, easily distinguishable from the surrounding 

 elements of the parenchyma (Fig. 25). They are of a gigantir- size, 

 and in some sections they seemed as if they were drawn out into 

 fibres in more than one direction. They have conspicuous \esic(dar 

 nuclei enclosing each a (U^eply stained nucleolus, which again gt-ncr- 

 allv encloses a vacuole. They are entire! v destitut<' of cell-walls, and 

 have a finely gramdar protoplasm. Their very appearance suggests 

 their nervous nature. i)ut more than that, oareftd examinations have 

 convinced me tliat these large cells are very constant in their position 

 and number. Thev are f~)und. namely, laterally and behind ihe 

 pharynx, and ran be seen in living specimens under the cover-glass, 

 especiallv well after the water has evaporated to a cei'tain extent. As 

 will be seen from the figure, they are situated symmetrically, right and 

 left, on ))oth sides of the pharynx. Ijesides the four cells on each side 

 and a median ventral one. drawn in the figure, I ha\'e counted 

 anotlier pair and a median unpaired one more posteriorly. T'here are 

 also similar <'ells. which are scattered aj)parently without symmetry, 

 around the brain, but always outside it in the mesen(-hyma. Two of 

 these are shewji in Fig. 17. 



Considering the form and appearance of these (^ells, the constancy 

 and symmetry of their position and luunber (at least in the more 

 anterior <Mies), together Avith the circiunstance that there are no 

 nervous cells m the brain or nerves, I am sti-ongjy inclined to ntti-i- 

 bute nervous functions to these gigantic cells ; but I have not been 

 able to trace anv direct connection with the nervous system. I have 

 tried methyl-violet and c()Ghineal stain. By the latter, they are but 

 slightly colored, and neither of these stains affords any better clue 

 into their exact natiu'e. They seem to l)e ditt'ereni from the remnant 



