104 



The small light-coloured, calcareous, spongite, or alcyonite, Plate 

 IX. Fig. 14, possessing somewhat of a conical form and a rugose sur- 

 face, and exhibiting, when examined with a lens, evident marks of an 

 original spongeous substance, was obtained by Mr. Strange from Swit- 

 zerland. A specimen, approaching exceedingly near in size and form 

 to the one here figured, was suspended in water slightly acidulated 

 with muriatic acid. As the acid acted on the carbonate of lime, the 

 membraneous part of the sponge began to appear ; and being libe- 

 rated, extended itself beyond the remaining solid mass, in tolerably 



coherent flexible flocculae. When it had been submitted so long; to 



i 



the action of the acid, that the carbonate of lime was nearly removed, 

 a dark brown reticular mass was left, bearing the general form of the 

 fossil, and manifesting its original spongeous reticulated texture. So 

 coherent was this mass, as even to bear its removal, by pouring into 

 another glass, without suffering any material injury to its form. It 

 was, however, at last broken, upon pouring additional water into the 

 phial which contained it. Another specimen, as similar in its form 

 and size as could be found, was then subjected to the action of the 

 acid for the purpose of obtaining a correct sketch of the remaining 

 membrane, which is given Plate IX. Fig. 15. 



The small calcareous fossils, Plate X. Fig. 7, 8, 9? and 10, are from 

 the Canton of Basle, in Switzerland. Their animal origin is rendered 

 evident by their alcyonic structure as discovered by the aid of a lens. 

 The specimen of a hemispherical form, delineated at Fig. 8, has a 

 central stellated opening, which has every appearance of having been 

 the residence of a polypous hydra, and which is surrounded by radi- 

 ating depressions, such as would seem to agree with the arms of the 

 animal. On close inspection, it is seen, that the whole substance of 

 the alcyonium is closely beset with innumerable minute openings, 

 which, in all probability, teemed with these extraordinary animals. 



The natural history of these substances teaches us, that individuals 

 of different species are frequently found growing adherent to each 



