H. B. Fantiiam 
395 
Fig. 9. Aggregata eberthi (Labbe). After Leger and Duboscq (1908). 
A. Sporocyst from the stomach of Sepia officinalis. Three sporozoites inside. 
B. Sporocyst showing valvular dehiscence, with two sporozoites free, the third 
still between the valves. Note posterior position of nucleus in the sporo¬ 
zoites. From gut of Portunus. 
C. Sporozoite at beginning of growth, after its passage through the gut-wall of 
Portunus. Nucleus has changed its position and become central. 
D. Further stage in growth; the parasite is now a young schizont. The nucleus 
(n) has become central, and the karyosome ( ky) has attained its highest 
degree of complexity. 
E. Schizont. Nuclear division and migration of small masses of nuclear material 
to the periphery. This and following stages are enclosed in a thin cyst in 
the peri-intestinal lymphoid layer, projecting into the haemocoel of Portunus. 
F. Schizogony. Further nuclear multiplication. 
G. Schizogony. End of nuclear multiplication; nuclei arranged along serpenti- 
form strands of protoplasm. Commencement of differentiation of merozoites. 
H. Merozoites (schizozoites) fully differentiated and arranged at the periphery of 
somewhat rounded masses of residual protoplasm. 
K. Merozoites dispersed and lying free among masses of residual protoplasm. 
at first arranged in the form of a reticulum, becomes peripheral and 
loses much of its capacity for staining. During this period a karyosome 
becomes evident (Fig. 9, D, ky) and gives off granules of chromatin into 
the cytoplasm. At this stage we have a young massive Gregarine 
provided with a spherical nucleus containing a large karyosome (Fig. 9, D), 
the organism being enclosed in a membranous cyst in the peri-intestinal 
lymphoid layer. The parasite is now a young schizont. The nucleus 
of the schizont, which possesses a nuclear membrane, complex karyosome 
and central reticulate zone (Fig. 9, D), then undergoes multiple division, 
giving rise to peripherally placed daughter nuclei (Fig. 9, E, F). These 
daughter nuclei are arranged along the edges of serpentiform, cytoplasmic 
islets produced by small invaginations of the mother cytoplasmic mass 
(Fig. 9, G). The daughter nuclei, with their cytoplasm collecting 
round them, give rise to rosettes of naked gymnospores or merozoites 
arranged around spherical masses of residual protoplasm (Fig 9, H, K). 
It is of interest to note that Leger and Duboscq found two forms of 
schizont. One form has a thick membrane and grows to about 50/x in 
length at the rate, roughly, of 1/4 per diem, attaining their full size in 
40 days. These are regarded as male Gregarines. The other form has 
a thin membrane and grows more rapidly and may attain a diameter of 
200 /a in 45 days, at the rate roughly of 4/4 a day. This is regarded as a 
female Gregarine. The cytoplasm of a Gregarine which has practically 
attained its greatest size contains certain granules some of which have 
staining reactions like those of chromatin, while there are others, which, 
