J80 



Metrospective Criticism, 



Mark of the column. 



the annexed figure 



Miller, who says, in a note, p. 67. of 

 his Crinoidea, " it is not unlikely that 

 the real joints forming the pelvis are so 

 much abbreviated as not to be visible ex- 

 ternally.'* I also send a figure {Jig. 35.) 

 taken from another specimen, in which 

 the plates, which Mr. Conway seems to doubt the existence of, 

 are better developed than in the specimen before mentioned. 



Mr. Conway asks, " Does it not always follow, as a matter 

 of course, that, when the column is enlarged and expanded at 

 its junction with the pelvis, the pelvis is also widened and 

 enlarged in the same proportion, as in the genus Apiocrinites ?" 

 and then says, " This, I think, cannot be denied." But, if he 

 had examined the genus Platycrinites, in which the column 

 occupies only a small portion of the centre of the pelvis, as in 



(taken of the natural size from 

 one of my specimens), and 

 compared it with the genus 

 Apiocrinites, I feel confident 

 that he would not have ha- 

 zarded a speculation for which 

 there is so little foundation ; 

 and, in my opinion, there is 

 much the same chance of suc- 

 cess for his speculation re- 

 specting the gradual change 

 [transition by an intervening 

 series of affinities] of En- 

 crinltes into Cyathocrinites ; 

 for though I have not seen the 

 specimen in the Geological 

 Transactions, yet in every specimen of Cyathocrinites that has 

 come under my observation, the plates of the body are alike in 

 number and position; and the superior parts, arms, hands, &c., 

 are invariably divided by what Miller terms cuneiform joints ; 

 whereas, in the Encrinites, the only plate which has this form 

 in the scapula, and the only division which takes place above 

 it is by a totally different process. 



A little further on, Mr. Conway states that it was because 

 he considered his specimen a nondescript that he communi- 

 cated it to this Magazine; but he most unaccountably forgets 

 himself. He did not communicate it as a nondescript, but as 

 the /% encrinite. He says (VI. ] 25.), — " I had my attention 

 amply rewarded by being furnished with a specimen of the 

 lily encrinite, of which 1 here send you a drawing, of the 

 nMural size : " and at the conclusion (p. 128.), — " If I am right 

 in supposing it to be the first discovered specimen of the lily 



a a. The three plates which form the pelvis 

 oia Platycrinltci. b, Mark of the column. 



