INFUSORIAL ANIMALCrLES. 91 



species of organisms, of whieli 15 were Infusorial. Some of these 

 species occur in Africa, yet none peculiar to that country. This is 

 remarkable, as those showers with the hot winds, which accompany 

 them, are said to come from the Sahara Desert, which must be 

 erroneous. Among the species were a Chili one, Synedra entomon. 



4. Sirocco dust from Genoa, May 16, 1846, contained 22 species 

 of Polygastric Infusoria, 21 of Phytolitharia, and three fragments of 

 plants. The colour is yellowish from oxide of iron, not grey like 

 African dust, and one-sixth to one-third of its weight was organic. 

 Ehrenberg remarks that these results show that the showers of dust 

 from the Atlantic, Malta, and Genoa, are alike, and also exhibit an 

 absence of true African forms. 



5. Sirocco dust fr'om Lyons, October 17, 1846, contains 39 species 

 of Polygastrica, 25 Phytolitharia, and 3 Polythalmia. The organic 

 matter forms one-eighth of the mass, and is mostly fr'om inhabitants 

 of fresh water. 



Nine showers of dust from the above localities, gives in the 

 whole, 57 species of Polygastrica; 46 Phytolitharia, and 8 Poly- 

 thalmia. Besides 7 kinds of plants and fragments of an insect. 

 Of marine species there are 17. Fresh water 102. There is no 

 evidence of volcanic origin. 



6. May 16, 1846. A second shower, on the same day at Genoa, 

 gave nearly the same species. 



7. Storm of red snow in Puster Valley, in the Tyrol, March 31, 

 1847, contained 22 species of Infusoria and an insect, besides 30 

 species of other organisms. Ehrenberg remarks the uniformity of 

 character of the dust over regions so widely separate, yet in nearly 

 a common latitude or zone, and in so many distinct examples 

 through a number of years is most surprising. 



8. In dust which fell in Italy 1803, and in Calabria in 1813, the 

 first contained 49 species, the latter 64. In both, all the species are 

 of fresh water habit, and one-fourth of them similar. The most 

 abundant were Eunotia amphioxys, four species of GalUonella, viz.^ 

 gramdata, crenata, distans, and procera. In both also were four South 

 American forms; Coscinodiscus Jiavicans from Peru and St. Domingo 5 

 Navicula undosa from Sm-inam; Stauroneis linearis from Chili aa4 



s 2 



