THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 203 



Heuiiegiiy aud Tlieloliau 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 he 

 defended ; no fact, however, comes to its 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, aud 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 ratlier frequently encounters spores 

 which are larger than the others and which exhibit a constriction (pi. 

 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 anditi the Microsporidia (whose spores offer much resemblance 

 to those of TheloJianla),v^'heYe they I av.' been seen by Pasteur/ who 

 considered them as corpuscles in process of division. On the contrary, 

 Balbiaui, who has studied them with care, regards them as the result of 

 malformations, a view which Henneguy and Thelohan adopt in the pres- 

 ent species. If fig. 12, pi. 1 1, 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). E. R. 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 



'Etudes sur les maladies des vers h sole, Paris, 1870. 

 * Journ. de Microgr., 1884, viii, p. 522. 



