763 



central point. This gives eight directions in which nuclear conjugation 

 is possible; namely, by way of the four corners and from the sides 

 of any cell. Any nucleus becoming amoeboid within any one of the 

 quadrangular cells of an epithelium such as has been described, with 

 a regularity almost equal to that of the squares of a chess board, 

 has a chance of conjugating with that of any one of eight neighboring 

 cells that are in contact and adjacent. 



The reconstitution of nuclei by the fusion or conjugation of 

 several similar nuclei within the same cell-body, as seen in the Ciliate 

 Infusoria, is not to be confounded with what is here described. In 

 the intestinal epithelium of land-Isopods a true nuclear wandering or 

 extension of nuclear pseudopodia may occur, leading to the conjugation 

 or union of the nuclei of different cells, somewhat as in sexual con- 

 jugation but without the fusion of the two cell-bodies in which the 

 nuclei are lodged. 



There apparently is an effect exerted by one of the nuclei upon 

 the other at a distance, or both seem to exert a reciprocal attraction 

 for each other at a distance, as in the case of sexually conjugating 

 nuclei. But here this is expressed by the reciprocal or one-sided 

 extension of nuclear pseudopodia from two independent nuclei toward 

 each other, though there is some evidence that both nuclei move 

 toward one another to some extent as in the conjugation of sexual 

 nuclei. Exactly what it is that develops this attraction between two 

 nuclei is as difficult to understand here as it is in the case of conjugating 

 sexual nuclei. The nucleoplasm does not apparently move as a whole, 

 but develops a streaming motion at one side as is shown in Fig. 1, 

 where the reciprocally attracted extremities of the nuclei are seen to 

 be composed of a dense protoplasm diminishing in depth of coloration 

 toward the other end of each, until it is sometimes difficult to dis- 

 tinguish its substance from that of the cell-body. This indefiniteness 

 of the hinder ends of the conjugating nuclei continues until a com- 

 plete fusion has taken place when a sharp outline and a homogeneous 

 distribution of the nuclear substance is again acquired. 



It may be well also to call attentiou to the existence of amoeboid 

 giant-cells in the pleural projections of land-Isopods. 



Transverse sections of these creatures, stained with Hover's car- 

 minate of ammonia, have revealed the existence of enormous amoeboid 

 cells in the pleural projections of the segments of the parseon or 

 body. These cells are sometimes quite two-thirds of a millimeter in 

 diameter and remind one of a very large Amoeba radiosa with 

 cylindrical, bent, club-shaped or flabellate pseudopodia. These cells 



50* 



