404 MONTGOMERY. [Vol. XV. 



size of the other ; but when three nucleoli are present, either 

 (i) one is particularly large, and the other two small; or (2) two 

 are large, and the third is much smaller than either ; or (3) all 

 three are large, the smallest being about one-half the size of the 

 largest. In the two cases of nuclei with four nucleoli apiece, in 

 the one there were two larger and two smaller nucleoli, in the 

 other one large and three small ones. 



The nucleoli vary from a spherical to an oval shape. In the 

 smallest usually no vacuoles (11. Vac.) are to be seen, but such 

 vacuoles are always to be found in the larger nucleoli. In the 

 largest there is usually a large excentric vacuole, while small 

 ones may or may not be present in other portions of the nucle- 

 olus. In nucleoli of medium size it is most usual to find a 

 number of small vacuoles. These vacuoles have already been 

 noticed in numerous other gregarines, but I would call especial 

 attention to a remarkable polarity of the nucleolus with regard 

 to their position. In all those nucleoli in which vacuoles 

 occurred, with the exception of not more than five or six, the 

 single large vacuole, or the group of smaller ones, was situated 

 at that pole of the nucleolus nearest the nuclear membrane 

 (Figs. 7-9, 16, 17-19). There are almost no exceptions to 

 this phenomenon in the smaller nucleoli, those, namely, in which 

 only a single small vacuole or a few small ones are present. 

 Accordingly, it would seem to be the rule that the vacuoles 

 first appear in that portion of the nucleolus which approaches 

 nearest to the nuclear membrane. The number and size of 

 these vacuoles increase with the size of the nucleolus ; or, as 

 is more usually the case, as the nucleolus increases in size they 

 gradually fuse together to form a single large vacuole, which 

 may occupy the greater part of the nucleolus (Fig. 15). Thus 

 the vacuoles first arise at one point in the nucleolus, so that 

 here one can speak of a polarity of the nucleolus ; but as the 

 vacuoles increase in number and commence to fuse together 

 the fluid substance of them begins to diffuse more widely 

 throughout the nucleolus, so that evidences of this primitive 

 polarity gradually become obliterated. 



The ground substance of the nucleoli is very finely granular, 

 and stains deeply red with eosin, and brownish red with the 



