380 Mr. Weaver's View of Ehrenberg's Observations 



mal body covered by a sliell, with the power of extending or 

 contracting itself at will. But when Diijardin expressly com- 

 pares the Polythalamia to the Proteus (Amoeba) of the Infu- 

 soria, such an association cannot be admitted, unless it be first 

 proved that a polygastric structure exists in those bodies. He 

 has given to them the new name of Rhizopodes. 



I showed, in 1837, that the Polythalamia could not well 

 possess an organization similar to that of the Infusoria, as not 

 a single known true species of Infusoria has a calcareous shell ; 

 and I had, in 1823, discovered, as I conceived, a true living 

 Polythalamia of earlier authors, resembling in organization 

 the very complex Flustra. The correctness of this view was 

 fully established in 1839, after having examined anew, ac- 

 cording to my improved method, the small Nautilus Orbicu- 

 lus of Forskal, which d'Orbigny designated in 1826 as Num- 

 mulina {Assilina) nitida^ specimens of which I had collected 

 from the sand of the Red Sea in 1823, and which I have 

 named Sorites Orbiculus. The result proved that the disc-like 

 shell was a Polypary, often composed of more than one hun- 

 dred single animalcules, the cells of which quite resemble those 

 of a Flustra, the animal putting forth and retracting from six to 

 eight tentacula. And I even discovered in the interior of the 

 single cells well-preserved siliceous Infusoria, the last food 

 taken by the animal ; and in some of them also small globu- 

 lar bodies, which, without much constraint, may be considered 

 as eggs. Though I had at an early period observed that the 

 disc was composed of many cells, yet I could not perceive an 

 opening to them; but the discovery of Infusoria in their in- 

 terior led me to consider by what means they could have been 

 introduced. Reflection reminded me that I had often seen 

 Coral animals which in the expanded state exhibited many 

 large bodies with tentacula and a large mouth, yet when con- 

 tracted left scarcely a trace of the openings through which 

 they were protruded from the common Polypary. As such I 

 remembered Pennatula, Lobularia^ Halcyonium and similar 

 forms, in which I had frequently observed, that in the skin of 

 the animal existed calcareous particles, which on the contrac- 

 tion of the skin so completely closed the opening as to render 

 it no longer perceptible. Renewed examination of the closed 

 surface of the cells of the Nautilus Orbiadus, Forskal, now 

 showed to me that in them also dendritic calcareous particles 

 exist, the close approximation of which closes the cell, so that 

 the cover of the cell is in fact the dried skin of the animalcule. 

 I now made an experiment in proof, by dissolving the small 

 shell in dilute muriatic acid, in order to obtain the animal 

 body ill a fvee slate; and it succeeded perfectly. 1 obtained 

 as many animalcular bodies as there were cells, connected to- 



