THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 203 
Henneguy and Thélohan add: 
Is it necessary to admit the existence of a plasmic mass [myxosporidium] which is 
completely transformed into sporoblasts? This mode of view can evidently be 
defended ; no fact, however, comes toits support, and it has the grave fault of deviating 
widely from what one knows of the development of the other species. On the whole 
we must admit that there is here a point in the history of our parasite which our 
researches have not elucidated, and the state under which it is presented constitutes 
a curious peculiarity which, at least in appearance, establishes an important distinc- 
tion between it and the other Myxosporidia. 
Abnormalities of development.—One rather frequently encounters spores 
which are larger than the others and which exhibit a constriction (pl. 
12, fig. 11). At first view one is tempted to question whether this is 
not a phase of division. Similar productions are rather frequent in 
Glugea and in the Microsporidia (whose spores offer much resemblance 
to those of Thelohania), where they lave been seen by Pasteur,! who 
considered them as corpuscles in process of division. On the contrary, 
Balbiani, who has studied them with care, regards them as the result of 
malformations, a view which Henneguy and Thélohan adopt in the pres- 
ent species. If fig. 12, pl. 10, be considered, it is quickly seen that this 
is the only interpretation admissible. One sees there 4 normal spores, 
and 2 larger structures constricted toward their middle and presenting 
attenuated extremities similar to the small ends of normal spores. The 
appearance of these elements and their dimensions cause one to think 
of 2 spores soldered by their large extremities. There can no longer 
remain any doubt in this respect if one considers that by supposing 
these spores separated the typical number of spores in the pansporo- 
blast is made up. In reality, then, the 2 spores in question have, in 
consequence of an accident which has occurred in the course of their 
development and by a process which we have not been able to follow, 
contracted an intimate adhesion at the level of their large extremity, 
the point where this soldering has taken place remaining marked by a 
constriction. The limited number of spores in each pansporoblast ren- 
ders the proof much more easy here than in Glugea and the Microsporidia, 
where the number of spores is much greater and not constant. 
[I can not see why these could not be more simply and better explained 
as malformations, the result of development from imperfectly segmented 
pansporoblasts, i. e., as developing from a quarter-segment of the 
pansporoblast which failed to divide completely. The partial fusion of 
2 spores where no pressure-atrophy of the shell could be assumed, seems 
very improbable. (cf. p. 180). R. BR. G.] 
Finally, although not pertaining directly to the Myxosporidia, in this 
connection the following from Kunstler and Pitres”? may be quoted: 
The small forms often show themselves constituted in such a manner that they 
appear to be in way of division (figs. 8-12). The multiplicity, the variety, and the 
constancy which these appearances present seem to show well that this is really a 
1¥tudes sur les maladies des vers A soie, Paris, 1870. 
2 Journ. de Microgr., 1884, vu, p. 522. 
