4S POSSIt ALCYONIA. 



from the superior to the inferior part of the fossil, and are 

 separated from each other by tuberculated ridges. At the 

 upper part has been a circular Opening more than half an 

 inch in diameter; and, at the lower part, is a rugged spot 

 as though the pedicle had been here separated : a circunw 

 stance indeed which renders its affinity to the alcyonium 

 Lfrne^fone described by Donati rather more doubtful. The substance 

 ilun.' *' °^ tn ' s f° ss, l app^rs to be a limestone, which, probably 

 from some tinge of iron, has obtained a reddish brown co- 

 lour. It is not of a very close texture, apparently from the 

 superadded calcareous matter not having accurately filled 

 all the interstices between the fibres. Hence numerous 

 ^inall openings are, even, in its present state, observable on 

 its surface, which on close inspection are seen to be such as 

 would result from a loose or spongy texture. 

 Spines men- Whilst treating of the alcyonium, of the species to which 

 Honed by Do- ^hig seems to approach, Donati particularly describes and 

 delineates the curiously formed spicule, which constitute a 

 part of its substance. The body, as well as the cortical 

 part, he remarks, is formed of two substances : the one of 

 which is fleshy, and the other osseous. The latter, he adds, 

 is formed into spines; which, near the cortical part, are in 

 great number, and closely intermingled ; being about the 

 length of two lines, and even longer. They are either of a 

 fusiform figure, or are finely pointed at one end, and then 

 gradually enlarge towards the middle: then, diminishing ' 

 as they lengthen, they divide into three sharp conical points, 

 around which are fixed numerous minute globular bodies, 

 which are chiefly found in the cortical part. 

 Strictures on A very strict examination, with a lens, of the surface of 

 Donau by numerous fossil alcyonia, did not however discover any ap- 

 pearance of similar spines, and almost induced me to a 

 ready concurrence with Plancus, who relates, that he has 

 dissected various bodies of this kind, and has seen the os- 

 seous fibres disposed in a radiated form ; but as to the won- 

 derful bark, the structure of which is so floridly described 

 by Donati, he says, I have not seen it, and observes that 

 the same thing has happened to him, with respect to the 

 * greater part of the figures in Donati's book, which, he says, 



are embellishments of the designer, drawn by the rule and 



compass,. 



