No. 1.] TWO NEW GREGARINIDA. 5 
divisions which result in eight nuclei. After the first nuclear 
division the resulting nuclei migrate to opposite poles of the 
sporogonium (Pl. II, Fig. 20 8). When the second division 
has occurred, two of the nuclei occupy the two poles of the 
sporogonium; the remaining two lie on opposite sides of the 
chief axis, half-way between the poles (Pl. II, Fig. 21). I 
am unable to say what the positions of the eight nuclei are at 
the close of the final division. The chromatic substance fre- 
quently. has the form of eight rings (Pl. II, Fig. 17), and these 
are usually arranged near the periphery of the cyst. With the 
metamorphosis of the rings into more homogeneous and elon- 
gated nuclei, they take up positions in the periphery of the 
cyst at or near its equator. It is frequently seen in cross sec- 
tions (Pl. II, Fig. 24) that the nuclei lie very near the periphery, 
and closely approximated in two rows of four each, which occupy 
opposite sides of the cyst. It is possible that each of the clus- 
ters is descended from one of the two nuclei resulting from the 
first division of the nucleus of the sporogonium; but I have 
not satisfactory proof of this. In other cases (Pl. II, Fig. 25) 
the nuclei lie near the periphery, but are not thus evenly 
divided in their grouping. In still other cases there is no evi- 
dence of a particular grouping; but this condition may be due 
to disarrangement caused by mechanical influences in killing, 
hardening, etc. 
During the metamorphosis of the nuclear substance the 
sporogonia produce two enveloping membranes: an outer one, 
which I shall call the capsule, and an inner one, which I shall 
call the cyst (Pl. II, Figs. 22, 23). 
The outer envelope is a very transparent, unstainable struc- 
ture of an elongated cylindrical or spindle-shaped form. It 
apparently has two openings, one at either end (PI. II, Fig. 31). 
Around each opening the wall of the capsule is thickened (a, 
Beit Figs: 22,°23,.209; 31). ° This’ thickening constitutes a 
somewhat rigid ring around the opening of the capsule, which 
is thus perhaps prevented from being accidentally closed. The 
two ends of the capsule generally differ slightly from each 
other; usually one end has more of a neck-like prolongation 
than the other, and it is this end which generally presents the 
