256 OTT. [Vol. VII. 



of clear, refractive, protoplasmic parenchyme. If the worm 

 remains quiet, the parenchyme is not seen to flow out. 



In sections, the appearance of the parenchyme varies accord- 

 ino- to the method of fixation. In sections from a worm 

 which has been fixed with corrosive sublimate (Fig. 3), the 

 parenchyme may be said to be made up of a large number of 

 irregularly distributed, amoeboid cells, and a finely granular 

 plasm filling the spaces between the cells. In many places the 

 cells may be seen to be closely massed together. The finely 

 granular plasm {Pro) takes a light purple stain with haema- 

 toxylin. In many cases the processes of the cells may be seen 

 to connect them with one another (Fig. 3). The cells vary 

 much in size. The largest of them are 4 yb, while the smallest 

 are 1.5 /u. in diameter. They are finely granular and are pro- 

 vided with round or oval, coarsely granular nuclei {N), which 

 become deeply stained in haematoxylin. The nuclei of the 

 largest cells are 1.5 /u., while those of the smallest cells are but 

 .3 /i in diameter. No nucleoli were seen. 



In sections of worms which have been fixed in chrom-osmic- 

 acetic acid (Fig. 4) the parenchyme may be seen to be made up 

 of an irregular network {X) of darkly stained, finely granular 

 material. In some places the network appears broken. The 

 spaces included within this network vary greatly in size and 

 shape. Some of them are not more than i /i, in diameter, while 

 others have a diameter of 5 yu. These spaces are filled with 

 a finely granular plasmic material, which with the haema- 

 toxylin did not become as deeply stained as the network. In 

 some spaces the plasm takes a dark purple stain while in 

 others it takes a very light purple stain. The network surround- 

 ing the dark spaces is not as broad and prominent as that sur- 

 rounding the lighter spaces. In many of these lighter spaces 

 the dark stain of the network may be seen to merge gradually 

 into the lighter stain of the plasm in the spaces. 



In many places circular or oval thickenings of the material 

 composing the network may be seen at the points where the 

 meshes of the network join. Sometimes dots which are like 

 these thickenings in structure are seen within the spaces and 

 free from the network. 



A few large amoeboid cells (O.) may be seen irregularly scat- 

 tered through the parenchyme and connected by their processes 



