300 Notice of Ehrenberg' s Memoir on Microscopic Life. 



No less than one hundred and twenty forms of siliceous and 

 calcareous animalcules and siliceous parts of plants were detected 

 by Ehrenberg among marine AlgEe brought from Vera Cruz by 

 his brother. Among the figures of these forms, we notice fig. 

 43, plate 3, (Planitlaria? Pelagi,) as strikingly like a fossil Poly- 

 thalamian shell, abundant in meiocene tertiary of Petersburg, Va. 



We pass now to the notice given by Ehrenberg of the locali- 

 ties of the United States, and we regret that our limits will not 

 allow us to insert his account without abridgment. 



" The first specimen of the infusoria of the United States which I 

 received, consisted of a portion of the fossil infusoria from West Point, 

 a specimen of which was sent over by Dr. Torrey, and received in 

 1839. Since that time the richest American materials have been ob- 

 tained from the United States, where the distinguished native men of 

 science have devoted themselves to the examination of these relations 

 with great zeal and success. 



" Richmond, Va. — A rich booty, consisting of the fossil forms alone 

 of Virginia, has been discovered by the exertions of Prof. W. B. Ro- 

 gers, the geologist of Virginia. Some of the species have been repre- 

 sented in Prof. Bailey's sketch of American Bacillaria, and he alludes 

 to the apparent resemblance of this geological formation to that of Oran. 

 The strict comparison of these relations possesses now a peculiar geo- 

 logical interest. I have taken the following list of 1 1 Virginian fossil 

 forms from Prof. Bailey's memoir. 



Bailey. Ehrenberg. 



1. Pyxidicula, fig. 2, = Pyxidicula cruciata. 



2. Gallionella sulcata, fig. 7, = Gallionella sulcata. 



3. Actinocyclus sulcata, fig. 10, == Actinoptychus octonarius.* 



4. " " fig. 11, ' = " senarius. 



5. Coscinodiscus lineatus, fig. 12, = Coscinodiscus lineatus. 



6. " patina, fig. 13, ==' " minor. 



7. " radiatus, fig. 14, = 



gigas. 



8. " argus, == " argus. 



9. " oculus iridis, = " oculus iridis. 



" In the specimens of the tertiary ' infusorial stratum' of Richmond, 

 kindly sent to me through Prof. Bailey from Prof. Rogers, I have, up 

 to this time, observed the following fifty forms, and have compared 

 them directly with the European forms, and also with those from Oran 

 in Africa. 



* Under the new genus Actinoptychus are now placed those species of the old 

 genus Actinocyclus which possess internal partitions or folds, while under the old 

 name are retained those in which the external rays are not connected with inter- 

 nal folds. 



