— 
se ——— path ep pen-teene — ~~ 
ieee tees - - FEE ———_ = SS = - ae 
- — — = ae ee = - 
704 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
nl eee coe . - 
a rey 
SO ica mm ly Since 
opposite sides; comparatively thin, and gradually tapering to a sharp. point. 
They are even in the most adult specimens uniserial at the proximal end, 
being composed of cuneate pieces to the fifth or sixth plate above the bifur- 
cation. The interlocking of the plates evidently took place in this species at 
a late period in the growth of the individual, for in a specimen in which the 
crown measures 22 mm., they are still uniserial to the very tips. The joints 
are rather long, and their surface is covered by small granules, so minute 
that they are visible only with the help of a magnifier. The edges of ap- 
i posed faces, from the costals up, are distinctly serrated, and the median por- 
‘y tions of the lower brachials are provided with a small transverse ridge. 
Pinnules closely arranged in the adult, separated in young specimens; the 
distichals. Arms from six to eight to the ray, given off alternately from | 
nc seem j 
He - joints very long. 
P | ~ Ventral disk hemispherical, slightly bulging at the sides, the plates tuber- | 
culous, large, and nearly of equal size. In some specimens the orals are some- 
i | what larger, and the posterior one sometimes bears two or three nodes 
/ instead of one. The covering plates:are arranged in rows, and pass out 
i | from the orals. Interambulacral pieces apparently four.. The anus ‘is located 
If low down at the side, and is very rarely seen, being most generally covered 
H | by a Capula. : 
| | Stem moderately large, circular at the extreme upper end, then turning | 
i : to elliptical. The joints gradually increase in length, until they are at the . 
| 
lower end of the stem three times as long as at the upper. The outer mar- 
: gin of the upper ones is surrounded by a row of small nodes placed at equal 
| distances, but on approaching the lateral appendages there are but two, 
| i which are larger and placed at the long diameter of the joints. Length of 
| | the stem not exceeding 25 cm., but generally shorter, terminating in a sharp 
i Pee. | point. Lateral cirri short and circular. 
| I Horizon and Locality. — Keokuk group. Found in large quantities and 
i : } excellent preservation at Crawfordsville, Ind.; rare at Keokuk, Iowa. 
| | i [ 3 Type in the Illinois State collection, Springfield. 
