342 Miscellaneous. 



last mentioued were the Island of Waigatsch and Nova Zembla in 

 the case of the first and Greenland and Newfoundland iu that of the 

 second *. 



In conclusion, the researches of M, Charles Rabot furnish us, in 

 the first place, with new and precise evidence for zoological 

 geograph}', and, secondly, enable us to assert that the fauna of the 

 fresh waters of Iceland, in that which especially concerns the Ento- 

 mostraca, presents mixed characters, recalling at once the analogous 

 faunae of Europe and, although in a less degree, of North America, 

 in the temperate and arctic zones. The explanation of this fact is 

 apparently to be looked for in the climatological conditions of 

 Iceland, since it lies, as we know, almost at the point of contact of 

 the warm and cold currents of the North Atlantic f. — Comptes 

 Itendus, t. cxiv. no. 6 (February 8, ] 892), pp. SIO-SIS": from a 

 separate impression communicated by the Authors. 



On a S/iorozoon parasitic in the Musdes of Decapod Crustacea. 

 By MM. F. HENNEGTjr and P. Th^lohan. 



In 1888 one of us % mentioned the existence of sporozoon para- 

 sites in the muscles of Palamon rectirostris and P. serratus. The 

 infected individuals are distinguishable at a glance by their opacity ; 

 they are of a chalky white, which contrasts with the normal trans- 

 parency of these Crustacea. This opacity is due to the existence in 

 the bundles of muscular fibrils of a considerable number of little 

 granular masses. Each of these masses represents a little vesicle 

 10 ^ in diameter, surrounded by a very delicate membrane and 

 enclosing eight refringent corj^uscles. The latter, which are slightly 

 pyriform, measure from 3 to 4 /x in their greatest diameter. Their 

 most swollen portion contains a clear vacuole, which occupjies more 

 than half of the corpuscle ; the small extremity is constituted by a 

 refringent substance. Owing to their aspect these cor])usclcs recall 

 those of pebrine and the spores of certain Myxosporidia, such as 

 those of the Gobies and the Stickleback. The fact that they are 

 met with exclusively in the muscular fibres of the infected prawns 

 had led us to assign these parasitic bodies to the Sarcosporidia, while 

 at the same time regarding them as transitional between these on 

 the one hand and the Microsporidia and Myxosporidia on the other. 



Unfortunately all the specimens of Palamon which we had 

 examined exhibited the parasite at the limit of its evolution, in the 



* Tide J. de Guerue and J. Richard, " Suv la faune des eaux douces 

 du Greenland " (' Comptes Rendus,' March 25, 1889), and " Revision des 

 Calanides d'eau douce " (Mem. Soc. Zool. de France, vol. ii., 1889). 



t Mohn, " Nordhavets Dybder, Temperatur og Stromminger " (' Norslce 

 Nordhavs-Expedition,' Christiania, 1887). 



X Henneguy, " Note sur un parasite des muscles du Palcemon recti- 

 rostris,^^ Memoires publics par la Societe pliilomathique a I'occasiou du 

 centeuaire de sa fondation, 1888. 



