348 
REPORT ON ZOOLOGY, MDCCCXLII, ETC. 
According to Quekett, an infusorial stratum, of twenty feet thick, has 
been found underlying the city of Richmond in Virginia, which contains 
forms agreeing completely with the species found in the North Sea. 
Navicula, Actinocyclus, Gallionella, and others, are specified. (Ann. 
Nat. Hist. ix. p. 66). 
A microscopical analysis, undertaken by Ehrenberg, of the natural 
paper-like mass found in Silesia in the year 1736, has given the follow- 
ing result: — That the chief part of the tissue consists of the Conferva 
fracta, in which nineteen species of Infusoria are imbedded (Bericht. 
fiber die Yerhandl. d. Akad. d. Wissensch. zu Berlin, 1841, p. 225). 
Stiebel has published his observations on the presence of Infusoria in 
Spas (die Grundformen der Infusorien in den Heilquellen, 1841). 
An infusorial, living in the sulphureous waters of Harrowgate and 
Askern in Yorkshire, according to Lankester, would seem to be the 
Astasia hoematodes, but he could not distinguish a tail, which is a 
generic character of Astasia (Ann. Nat. Hist. vii. p. 109). 
Focke has declared the lowest invertebrata, namely, the Monades, to 
be too minute for physiological investigation. No explanation, there- 
fore, can be given of these animals, either in regard of their generation 
or of their vegetable or animal distinction, or of the function of the 
parenchyma, and the like (Bericht. fiber die Versamml. der Naturf. u. 
Arzte zu Mainz, 1842, p. 227). In the Bacillaria and Navicularia, 
particularly the Navicula viridis, Focke observed an evident open longi- 
tudinal cleft, through which it receives nourishment, so that no doubt can 
exist of the animal nature of this being ; but, on the other hand, it was 
very ditficult to distinguish it in the Desmidiacea, as they continued 
eight days, and longer, in the act of their transverse section, without 
essentially altering during this time. Besides the Desmidiacea, the 
Diatomea and Closteria have been also separated by Dujardin from 
the animal kingdom (Hist. Natur. des Zooph. p. 668). 
In the contributions to the Fauna of the Infusoria at Vienna, pub- 
lished by Riess, 360 species are mentioned according to Ehrenberg’s 
system (Beitrage zur Fauna der Infusorien um Wien, 1840). 
Ehrenberg has accurately and ingeniously arranged, in his treatise, 
Das unsichtbar wirkende Leben, Leipzig, 1842, his previous important 
researches of many years, on “ invisibly-working organic life.” 
The two following works, for which that of Ehrenberg has furnished 
the groundwork, are useful as hand-books. Kutorga : Naturgeschichte 
der Infusionsthiere, vorzfiglich nach Ehrenberg’s Beobachtungen bear- 
beitet, 1841 ; and Pritchard : a History of Infusoria, Living and Fossil, 
arranged according to “ die Infusionsthierchen ” of Ehrenberg, 1841. 
392 
