54 
far the greater part of the cyst consists of an immense 
number of spores. The endoplasm is the seat of spore- 
formation. In the Microsporidia, this starts and pro- 
ceeds either from one centre or from several. In the 
latter case, each centre comprises (at first) a single 
nucleus and a small portion of the cytoplasm in the 
immediate neighbourhood, the whole becoming segre- 
gated to form an “organella” of reproduction. Hach 
such centre is termed a pansporoblast. When, as in the 
one family, including Thelohania, Pleistophora, &c., there 
is only one, it signifies that the whole dividual becomes 
a reproductive organella and commences to sub-divide up 
into sporoblasts and spores (just as, for instance, a 
Gregarine does). So that, in Plezstophora, a ripe infec- 
tion consists of a number of relatively small indi- 
viduals, each being a single cluster of spores. This 
fact, together with the blunter and thicker shape of the 
spores in this genus, leads me to surmise that Linton’s 
sporocyst from the liver of Rhombus triacanthus (see above) 
was probably a Plezstophora. 
To return to our Glugea specimen. The endoplasm 
contains a great number of spore-forming organelle in 
various stages of development, from little uninuclear ones 
to large ones which are practically clumps of sporoblasts 
(spbl.). The actual transition from sporoblast to spore 
is extremely difficult to follow in the case of these minute 
spores; for a full account of the development in the large 
forms, Thélohan’s paper should be consulted. I may 
add, in passing, that anyone who desires complete informa- 
tion on the group, cannot do better than read Minchin’s 
up-to-date and concise résumé (5). Scattered about in 
the endoplasm, and also oc easionally met with in the 
central mass, are large, sometimes drawn-out nuclei (n.) 
with fragmented chromatin and a distinct nucleolus (?). 
