MUSEUM OF COMPARATIVE ZOOLOGY. 135 



the right are still imited to each other by strands at the comers. Very 

 similar tripartite divisions were found by Overlach ('85, Plate XI. Figs. 

 35 and 41) in the epithelium of the cervix uteri. In two other cases, 

 I have found one of the daughter nuclei in a late stage of division 

 (Figs. 31, 32) itself elongating and undergoing constriction. It will 

 be noticed that the constricted daughter nucleus is considerably larger 

 than its mate. 



I have found but two cells with more than three nuclei, and these both 

 contained four. This condition is brought about by the division of both 

 nuclei of a binucleate cell. On a ■priori grounds, one would reason that 

 quadrinucleate cells would be nearly as abundant as those with three 

 nuclei, for, apparently, it must often happen that a pair of daughter 

 nuclei, arising as they do by a symmetrical and accurate constriction, 

 are ready to divide at almost the same moment. Yet there are doubt- 

 less influences which operate to prevent the division of one of the 

 nuclei. Although it is of course impossible to generalize on the char- 

 acteristics of quadrinucleate cells, it may be of interest to mention the 

 peculiarities of the two found. They are both large cells, of nearly 

 equal width at the ends, and the breadth of both exceeds half the 

 length. In one, both pairs of nuclei lie transversely, showing that the 

 second divisional plane was at right angles to the first. In the other, 

 represented in Figure 33, the lower pair of nuclei lie in the longitudinal 

 axis, the upper pair almost transversely. One of the quadrinucleate 

 cells is considerably larger than any cell near it, while the other (Fig. 

 33) though by no means small, is of much less dimensions than the im- 

 mense bi- and uninucleate cells around it. I am unable to assign any 

 reason for the mnltinuclear condition of this cell. One fact, however, 

 is worthy of note. The united volume of its four nuclei does not 

 exceed the bulk of the single nucleus of a neighboring cell. One can- 

 not, of course, ascertain what the size of the primitive nucleus of the 

 multinucleate cell was, but it is very improbable that it exceeded in 

 volume the nucleus of the uninucleate cell in question, for the latter 

 cell is considerably the larger of the two, and throughout this serosa the 

 size of the nuclei bears a direct ratio to the size of the cells. 



As regards the influence or influences impelling nuclei to divide 

 independently of the division of the cell, nothing very definite can be 

 stated. It is certain that the absolute or relative size of the cell has little 

 or no influence upon the division of the nucleus. There are cells of all 

 sizes, from the largest to the very smallest (Fig. 3), which are binucle- 

 ate ; and it is usual to find, side by side with bi- or multinucleate cells. 



