108 CLEIOCKINUS. 



DEFINITION OF THE GENUS. 



The facts herein brought out necessitate a new definition of the genus, 

 which I propose as follows : — 



Cleiocrinus Billings. 



Generic Diagnosis, amended. — Calyx large, conical, or pyriform ; pliant ; 

 plates joined by loose suture. Base dicyclic ; infrabasals five, invisible ex- 

 teriorly. Basals and radials not in normal succession, but alternating with 

 each other in a horizontal ring of ten plates surrounding the infrabasals and 

 projecting downward over the column. No interbrachials, except at the anal 

 side ; anals in vertical series, resting on truncate posterior basal, and ex- 

 tending high up between the rays. Bays and their divisions up to the free 

 arms contiguous and interlocking ; brachials bifurcating several times in the 

 calyx, giving oft' fixed pinnules, which are incorporated by lateral union 

 with adjacent brachials and become free between the arm bases. Arms 

 simple, uniserial, and pinnulate. Column obtusely pentagonal, or nearly 

 round. 



SPECIES. 



Billings described three species of this genus : — C. regius from the 

 calyx, and ('. grandis and C. magnificus from stem fragments only. I see 

 nothing to indicate any substantial distinction between the stems of C. 

 regius and C. grandis, — both being pentagonal, and the difference in size 

 not being very great. The stem fragment which he named C. magnificui 

 (Dec. IV., PI. V., Fig. 3) is round, with proportionally much thinner 

 columnars, and of very large size. It is probably from the lower part of the 

 stem, where it seems to lose its angularity and become round. In the 

 new material there is another fragment, still larger, being over an inch in 

 diameter, which is also round ; the uncrushed part of it is figured on Plate I., 

 Fig. 12. The large crown E. (PI. I., Fig. 11), and the long stem already 

 mentioned — thirty inches long — came from the same quarry, and may 



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