151 



to an. animal of the genus alcyonium, I do not in the least 

 doubt, nor that the perpendicularly disposed lamellae are the muscu- 

 lar organs-, by which the animal was enabled, as in the fossil just de- 

 scribed, to elevate the more central part of its base, and thereby 

 produce that vacuum by which its attachment to any particular body 

 would be secured. 



In two several parts of the stone, cavities are also observable, which 

 seem to be the moulds formed on the outer surface of the animal, as 

 the preceding appeared to be formed on the inner. On the inferior 

 surface of these cavities, which are circular, radiating stria3 are ob- 

 servable, and which, apparently, answer exactly to the disposition of 

 the inferior part or basis of the Iamella3, already described as forming 

 the projecting part in the cavity of the supposed animal. This flat 

 circular surface, I am therefore disposed to consider as the impression 

 formed by the inferior flat part of the alcyonium, corresponding with 

 the inferior surface of the fossil already described, Plate X. Fig. 1. 



Previously to my quitting this tribe of zoophytes, I shall avail 

 myself of the opportunity afforded me by my friend Dr. Menish, 

 of placing before you a very curious fossil from his select and elegant 

 collection. This fossil, which is represented Plate XII. Fig. 3, is chiefly 

 composed, judging from its weight and hardness, of flint, a nd was 

 found in Essex. It is formed of roundish but rather flat bodies, in 

 the centre of each of which is a small depression. From two of these 

 bodies being, even at present, connected by a small process, and by 

 small protuberances, like the terminations of such processes, appearing 

 on the sides of several of these bodies, there is great reason to sup- 

 pose that they were all originally thus united. From all these circum- 

 stances. I trust that it will not be too much to presume, that this fos- 

 sil is of the same nature, if not of the same species, with those which 

 are represented Plate VIII. Fig. 10. 



The almost transparent chalcedonic alcyonite, from France, Plate 



