344 Mr. F. B. Meek on the Genus Lichenocriims. 



to render it at least improbable that it had ever supported a 

 body at that end. 



Two other solutions of the difficulty suggest themselves, 

 one of which is, that possibly the specimens, as we now see 

 them, may not be the mature condition of the animal, but 

 only one of the stages of development of some crinoid, which, 

 if known in its adult condition, is supposed to be an entirely 

 distinct type. The other is that the disks, as we now see 

 them growing fast to other bodies, may be the adult condition 

 of a crinoid that in its earlier stages of growth was supported 

 on its little column, as in other types, being otherwise free, 

 and that at a later period of its growth the column became 

 free at its lower end, and was for a time trailed about by the 

 floating body, which finally inverted itself and grew fast to 

 other objects by what was originally its vault. The fact, 

 however, that these disks attain a diameter of at least half an 

 inch, with the elongated appendage four inches or more in 

 length, would, even if known analogies supported such a 

 view, seem to be a very strong objection to the conclusion 

 that these are immature or embryonic forms ; while, to say 

 nothing of other strong objections tliat naturally present them- 

 selves against the last mentioned suggestion, the occurrence of 

 these disks of all sizes, from the largest down to others less 

 than a tenth of an inch in diameter, all alike growing fast to 

 other bodies by the side opposite the column-like appendage, 

 seems to demonstrate that this is their mode of growth from 

 the first*. 



In view of all that is now known of this curious fossil, it 

 seems to me, without undertaking to express a positive opinion 

 on the subject, that the weight of evidence (supposing that 

 these disks are really the hndy of the crinoid) favours the con- 

 clusion that the long appendage is a ventral tube ; but if the 

 ajypendage is a column^ then I should incline to the opinion 

 that the disk is a peculiarly organized root, and that the body 

 may be yet unknown, unless as an entirely distinct crinoid. 



For the use of specimens of this fossil I am under obliga- 

 tions to Mr. C. B. Dyer, Mr. U. P. James, Mr. D. H. Shaffer, 

 Dr. H. H. Hill, and Dr. R. M. Byines, of Cincinnati. Mr. 

 Dyer's collection, however, contains much the most complete 



* In a few very rare cases the disk has been found detached and show- 

 ing the flat side marked by very regular radiating striae. It is almost cer- 

 tain, however, from the fact that hundreds of specimens have been found 

 growing flrmly to other bodies, that these few separated individuals had 

 become detached by the disintegration of the object upon which they 

 grew, and that the radiating striae are only the edges of the lamellae 

 within, exposed by weathering, as we also sometimes see on the upper 

 side of weathered specimens. 



