488 F. W. GAMBLE AND J. H. ASHWORTH. 



and the broad end of the giant-cell. Here they forui a distinct 

 deeply staining area which may be observed in almost every 

 giant-cell. In a few cases a transparent body (•004 mm. in 

 diameter) appears to form the focus towards which the lines 

 of granules converge. The granules are here rather larger 

 and stain more deeply than those of the rest of the cell-body. 

 The whole appearance is accurately recorded by Miss Lewis 

 in Maldanids, with whose descriptions our own preparations 

 from Arenicola Grubii closely agree, except that we have 

 not satisfied ourselves that a " centrosome '' is actually 

 present (PI. 28, fig. 77, Gentr.). 



The nucleus is a large subspherical structure, averaging in 

 the larger giant-cells 20 fx in diameter. Within the distinct 

 nuclear membrane are the chromatin network, the fluid 

 contents, and usually one lens-shaped nucleolus about 6 ju in 

 diameter. The nucleus is always excentric, and is usually 

 placed near the broader end of the cell. 



We have reserved to the conclusion of this description 

 the most debatable element of structure, namely, delicate 

 fibrillse distinct from the glia-fibrillae of the sheath or from 

 any other usual cell-element, and which we conclude repre- 

 sent Apathy's neuro-fibrilla3. They are by no means to be 

 seen in every preparation, even of those produced by the 

 same method, but in successful cases they stand out very 

 clearly, especially in the cell process (see PI. 28, figs. 70 and 76, 

 nllse.), whose structures we have so far entirely neglected. 



The cell-process is enveloped by a fibrillar nucleated glia- 

 sheath, which is continuous with that of the cell-body. 

 The protoplasm within this sheath is clear, and, though finely 

 granular, does not stain, or at most very lightly indeed. It 

 is penetrated by delicate, darkly-staining fibrillse, which do 

 not branch in the process, but on entering the body of the 

 cell break up into at first a few branches (PI. 28, figs. 70, 71, 

 76, Nllse.) and these into still finer ones as they approach the 

 basal part of the cell. Fi-equently they are only stained as 

 they enter the cell, and then they appear to end abruptly, but 

 in successful cases (and especially in horizontal sections 



