No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
this form. Only two individuals of Carinella were examined 
(both from Bergen, Norway); in the one all the gregarines were 
large, in the other of a smaller size.) 
The nucleoli are nearly always more numerous than in the 
preceding species of gregarine, the number varying from four to 
about twenty-six, in those stages found (Figs. 22-35). I n the 
larger nuclei they are usually more numerous than in the smaller 
ones, but exceptions to this rule are quite frequent. In the 
same nucleus some are nearly or quite spherical, others very 
irregularly lobular in outline. Their size within a given nucleus 
is also very variable, though as a rule they are unequal in their 
dimensions. In the larger nuclei the nucleoli are larger (or at 
least some of them are) than in the smaller nuclei. In a given 
nucleus there may be either (1) from two to four larger nucleoli 
and a number of smaller ones ; or (2) a single large nucleolus 
and several much smaller ones. In the smaller nuclei the 
nucleoli are more equal in size than in the larger ones. The 
largest nucleoli in a nucleus are as a rule of oval or spherical 
form, with regular contour (an exception is seen in Fig. 26) ; 
the irregularly lobular nucleoli (Figs. 23, 25, 27, 28, 33) are 
usually of medium or small size. There is no apparent regu¬ 
larity with regard to their distribution in the nucleus. None of 
the nucleoli appear to have limiting membranes. 
All these gregarines were fixed with alcoholic solution of 
corrosive sublimate. With the double stain, haematoxylin and 
eosin, the larger nucleoli were stained with a deep blackish 
red, the smaller ones either of the same color or a clearer red ; 
all became stained so intensely by this method that the vacu¬ 
oles in them were greatly obscured (Figs. 27 and 28). 
The Ehrlich-Biondi method produces a yellowish brown or 
reddish stain of the nucleoli, differences of stain being observ¬ 
able in the different nucleoli of the same nucleus (Figs. 26, 
31-35). This staining method brings out very clearly the 
vacuoles in the homogeneous (?) ground substance of the 
nucleolus ; the structureless substance of these vacuoles 
stains less intensely than the enveloping substance. Vacu¬ 
oles are absent in the smallest nucleoli, as well as in those of 
irregular form ; in the larger ones they are almost invariably 
