Miscellaneous. 
195 
I have met with two species — one in the liver of the stickleback, 
the other in the testis of the sardine. Both belong to the genus 
Coccidium , as characterized by the successive works of Leuckart, 
Schneider, and Balbiani ; that is to say that, on arriving at their 
full development, they form four spores, each of which encloses 
two falciform bodies. 
(i.) Coccidid of the Stickleback (Coccidium gasterostei, sp. ni ). — I 
discovered this species in April of the present year in sticklebacks 
( Gasterosteus aculeatus) from the marshes of Yilaine, in the Morbi- 
han. This Coccidid is of small size and its cysts only measure 16 
to 18 g. It lives in the hepatic cells, undergoing the whole of its 
development in the same cell. I have several times observed cells 
containing three or four cysts. These facts are easily made out by 
teasing a portion of diseased liver. By making sections of the 
organ, after fixing, hardening, and embedding it in paraffin, I have 
been enabled to discover the developmental phases and to study 
them much more easily than by teasing ; but it was by means of 
the latter method alone that I succeeded in determining the exact 
relations of the parasite to the hepatic cell. I have not been able 
to observe the very young stages. On attaining its full develop- 
ment Coccidium gasterostei measures, as I have already said, 16 to 
18 g in diameter. It is a little spherical mass of plasma enclosing 
a very large number of coarse globules ; these are tolerably retrac- 
tile, but do not affect polarized light. 
At this point the Coccidium encysts, that is to say the plasma 
surrounds itself with a delicate transparent pellicle of a uniform 
spherical shape. The plasmic mass then contracts, leaving an 
empty space between it and the wall of the cyst. The nucleus lies 
in the centre of the plasma, though the granulations of the latter 
sometimes render it difficult to determine its presence. After a 
short time it migrates to the periphery and divides. The small 
size of the nucleus renders the task of observing it an extremely 
delicate one, and I have therefore not been able to follow all the 
stages of its division; I have, however, found figures sufficiently 
distinct to enable me to recognize karyokinesis. 
The two nuclei resulting from this division divide in their turn, 
and we finally get four nuclei placed at the extremities of two 
perpendicular diameters of the plasmic sphere. The latter then 
splits up into four little spheres, each of which encloses a nucleus. 
This segmentation of the primitive mass appears to take place very 
rapidly, and most probably in the majority of cases it does so all at 
once. There is sometimes a second stage, which, by reason of its 
extreme rarity in my preparations, is probably a very short one, 
that is supposing it to be constant. The four little nucleated 
spheres are sporoblasts. Their nucleus divides (always indirectly) 
and the binuclear sporoblasts then lengthen out, surround themselves 
with an envelope, and reassume the characters of typical spores of 
Coccidium , that is to say, each of them encloses two falciform bodies 
provided with a nucleus. During the formation of these sporozoids 
there is to be seen a residual granular mass, which diminishes little 
by little during their increase in size (Schneider’s residue). The 
mature spore is fusiform in shape and 10 g long by 4 to 6 g wide. 
