214 PALEONTOLOGY OF ILLINOIS. 



Genus CCELOCRINUS, M. and W. 



(xodos, hollow; xpivov, a lily; in allusion to the concave base.) 



Sphserocrinus, Meek and Worthen, 1865. Proceed. Acad. Nat. Sci., Philad., p. 154; 



(not Roemer.) 

 Ccelocrinus, Meek and Worthen, 1865. lb., p. 273; (not Coeliocrinus, White, 1863.*) 



In this type the formula is that of such species of Actinocri- 

 nus as have no secondary radials, and but few anal and inter- 

 radial pieces, excepting that it has its opening lateral, as in 

 Amphoracrinus and Agaricocrinus, while its base is concave, as 

 in the latter genus. From Agaricocrinus, with which it per- 

 haps most nearly agrees, it differs in having greatly less robust 

 arms, which come out around the summit, instead of on the 

 horizon of the lower part of the body. It also differs in having 

 its first anal and first radial pieces curved up so as to form 

 nearly half the height of the lateral walls, as well as under, so 

 as to form most of the under side of the body. From Arnplio- 

 racrinus it differs in the sunken character of its base, the con- 

 cavity of the under side, and the curved character of its first 

 anal and first radial pieces, as well as in having weaker arms, 

 and its arm-bases not projecting — there being but a single 

 brachial piece to each division of each ray, soldered into the 

 walls of the body, and these rest directly upon the third 

 radials. The small lateral opening of the summit is on the 

 same horizon as the arms, and rather in a slight depression 

 than upon a protuberance, as we usually see in Amjp7ioracrinus 

 and Agaricocrinus. 



It is possible that we should place this as a subgenus, either under Agarico- 

 crinus or Amphoracrinus, though we are at present inclined to regard it as 

 being distinct from both. 



* Some have objected to the name Coelocrinus, because it is thought to be too near 

 Coeliocrinus, of White, previously used for another type. As Dr. White's name, how- 

 ever, was derived from the Greek for the belly, and the two names are otherwise quite 

 as distinct as many others retained in various departments of natural history, we can- 

 not admit the force of this objection. 



