FOSSIL ALCYONIA. 49 



Compass, rather than in agreement with the truth and sim- 

 plicity of nature*. 



Being in possession of another specimen of this kind, A s P ecin ] ea 

 01 r . examined 



formed of a much harder and closer stone, ami which from 



its appearance I supposed to be invested with its cortical 



part, I resolved to sacrifice it to a more rigorous search for 



the spines described by Donati, concluding that, since all 



agreed as to their differing in their bony hardness from the 



other parts of this animal, I should at least discover some 



traces of them, although I might not be able to make out 



their form. 



This fossil was therefore subjected to the only modes of by cutting, 

 dissection which I could employ with substances possessing 

 a stony hardness. A polished section of it was obtained on 

 different parts of it, and at different depths; by which the 

 peculiar spongeous structure, already noticed as belonging 

 to these bodies, was perceived; but no appearance of spines 

 could be detected. 



The specimen was then immersed in dilute muriatic acid, ancl digestion 

 and examined at different periods, to ascertain whether the acic j 

 new surfaces thus obtained displayed any particular appear- 

 ance. After rather more than a quarter of an inch of its 

 substance was thus removed, I was pleased to find, with a 

 lens of moderate power, several cruciform spines, formed, which exhibit-. 

 as it were, by two fusiform bodies, not an eighth of an inch ed the s P inei * 

 in length, crossing each other at right angles, and termi- 

 nating at each end in.a very sharp point. 



When these bodies were first discovered, the specimen These an hy« 



was still wet with the water, with which the acid had been d ">i )haoous 



chalcedony 



removed. In this state they possessed a considerable degree 

 of transparency, which they rapidly lost, as the water eva- 

 porated : so that when dry, they were completely opaque, 

 and of a chalky whiteness. From their possessing this hy- 

 drophanous quality, and from their having withstood the > 



action of the muriatic acid, there appears to be the greatest 

 reason for supposing, that these bodies, which were origi- 

 nally the spines of the animal, are now formed of an hy- imbedded in 



chalk, 



* De Conchis minus notis, App. II, page 115. 



Vol, XXHI May, 18Q9. E drophauous 



