Miscellaneous. 343 



sporiferous stage, and wc had no idea as to its mode of deve- 

 lopment. 



In 1891 Garbini * found in the muscles of PaJcemonetes varians, 

 collected in the neighbourhood of Verona, a sporozoon very closely 

 allied to that of PaJcemon recti rostris ; it appeared in the form of 

 spindle-shaped vesicles enclosing eight pyriform spores. The author 

 did not succeed in observing the first stages in the development of 

 this ])arasite, which he regards as belonging to the Sarcosporidia. 



At the same [jcriod one of us f mentioned the existence of jjara- 

 sites in the muscles of Callioin/tnus h/ra and of Cottus .fcorj)ius, and 

 drew attention to the relations exhibited by these organisms with 

 the parasite of Palcemon and that discovered by Glugeiu the Stickle- 

 back, and for which he proposed the name Glugea microspora. By 

 prosecuting the study of these sporozoa he has been able to deter- 

 mine the existence in the spores of Glugea of a capsule with a spiral 

 filament J, an element which, as we know, is characteristic of the 

 Myxosporidia. He has since succeeded in making the same obser- 

 vation with regard to the spores of the parasite of the muscles of 

 Cottus. 



It was therefore to be presumed that the parasite of the muscles 

 of Palamon likewise exhibited this character, and should also be 

 assigned to the Myxosporidia. 



An observation has quite recently been made which confirms this 

 hypothesis and enables us to study the development of the spores. 



Through the courtesy of Prof. Giard we have been able to 

 examine a specimen of Crunr/oa vulgaris from Boulogne, which 

 exhibited the chalky appearance already mentioned in connexion 

 Avith the infected prawns. On making a microscopical examination 

 we found all the muscles invaded by a parasite identical in aspect 

 with that of Palcemon, from which it differs only in being of larger 

 dimensions, the spores measuring from 5 to 6 /^ instead of from 

 3 to 4 ju. 



In this case also the spores are arranged in groups of eight in 

 vesicles with very delicate walls. They are pyriform and possess 

 an envelope which resists potash, and their large extremity is occu- 

 pied by a clear vacuole, as in the spores of the parasite of Palcemon, 

 C'otlus, &c. 



By treating them with hydrochloric or nitric acid we have been 

 able to determine the issue of a filament at the level of the small 

 extremity. It is nevertheless very difficult to produce the emission 

 of this filament, and we have only observed it a very few times in 

 spite of repeated efforts in this direction. 



In addition to the vesicles containing eight spores, which repre- 



* Garbini, " Contributo alia conoscenza dei Sarcosporidi," Eeddiconti 

 della R. Accad. dei Lincci, vol. vii., February 1891. 



t Tlielohan, " Sur deux Sporozoaires nouvoaux, parasites des muscles 

 des Poissons," Coniptes Rendus de I'Academie des Sciences, January 

 1891. 



X Thelohan, " Note sur la Glucjea microspora," Comptes Rendus de la 

 Societo de Biold-iif, .January .'50, lh92. 



