No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
ined. Form : elongate, slightly larger at one end than the 
other, the thinner end sometimes flattened, slightly curved or 
sickle-shaped ; the greatest diameter is found in the region of 
the nucleus, which is situated nearer to the larger than to the 
smaller end ; both ends of the animal are rounded. In one 
individual (Fig. 2) the surface of the body was slightly furrowed 
in a spiral direction. Nucleus large, with a very thick mem¬ 
brane, and seldom oval, usually irregular in outline. In a single 
case (Fig. 1) two nuclei were present in one gregarine (the 
youngest individual seen), the two nuclei were of unequal size, 
though each contained a single nucleolus. Kolliker (’49) has 
described a gregarine with two nuclei ; I am unacquainted with 
any other cases. Sporocysts were not observed ; but in one 
case the cytoplasm was quite densely filled with minute spher¬ 
ical and oval bodies, which stained lightly with eosin, and in 
each occurred a small granule (this staining with haematoxy- 
lin) ; in the same individual a normal nucleus was also present 
(Fig. 4). These small bodies cannot be other than spores, even 
though they occur in the endoplasm of a gregarine in which 
a nucleus occurred at the same time; this observation stands in 
no accord with what has thus far been described of the sporu- 
lation among gregarines, and I am thoroughly at a loss to 
explain the phenomenon. These gregarines occurred only in 
the posterior intestine of Linens , but were not present in all 
the individuals of this nemertean sectioned. The absence of 
synzigia, the transverse furrows of the body, and the oval-shaped 
spores would relegate this form to the neighborhood of the 
genus Gonospora of Schneider.) 
In the smallest nuclei found (the size of the nucleus stands 
in some degree in proportion to that of the animal) only one 
nucleolus was present (Figs. 3 and 5) ; in all the larger nuclei 
their number varied from two to four, though since four nucleoli 
were found in only two cases, two or three nucleoli may be 
regarded as the usual number in the larger individuals. As 
an inspection of Figs. 3-19 shows, the comparative size of 
the nucleoli within the same nucleus is very variable, and the 
nucleoli of one nucleus are always of unequal size. When only 
two nucleoli occur, one is about one-half or three-quarters the 
