NIAGARA GROUP. 



201 



591. 2. LECANOCRINUS ORNATUS {n. sp.). 



PL. XJLIV. Fig. 2 a- m. 



Calyx cup-form, spreading to the commencement of the arms, above this point the sides are 

 nearly straight ; pelvis composed of three minute anchylosed plates ; second range, or costal 

 plates, having two pentagonal, one regularly hexagonal, and two unequally heptagonal ; scapular 

 plates heptagonal, succeeded by two arm-joints, upon the upper of which, or the hand-joint, 

 commence the subdivisions which are once or twice repeated • a single quadrangular inter- 

 costal plate on one side, and above it two interscapular plates, succeeded by two others, 

 beyond which they have not been traced ; surface ornamented by minute points or tubercles, 

 which, towards the margins of the plates, extend into stride or ridges, meeting similar ones 

 from the edge of the adjoining plate ; column round ; joints thin, unequal, alternating more 

 or less regularly, articulating surfaces crenulated near the margin ; canal at base of cup 

 pentangular. 



This neat little species is very readily distinguished from the preceding by its proportionally 

 smaller plates, and in the wide separation of the first divisions of the arms, showing a tendency 

 to free branching, and never having the close arrangement so constant in the other species. The 

 arms and fingers can readily be traced to the third division, beyond which they are closely 

 incurved, thus making at least forty divisions at the extremities of the fingers. 



The upper joints of the column are thin and somewhat irregular, crenulated near the margin, 

 and nearly smooth towards the centre ; canal at this point, minute, pentangular. The inside of 

 the pelvis is marked by a triangular impression with raised margins, the angles alternating with 

 the divisions of the plates (figs. 2 a!, e). The edges of the pelvic plates are slightly crenulated 

 at the inner and outer margins, the intermediate space being granulated. A single fragment of 

 a column, having some characters in common with the few joints attached to fig. 2 6, is shown 

 in fig. 2f; but the canal is round, though the crenulations are marginal. 



Fig. 2 a. A small specimen of this species. 



Fig. 2 b. A larger individual, showing same form as the preceding. 



Fig. 2 c. Base of the anchylosed pelvic plates, with a single joint attached. 



Fig. 2 d. The interior of the same. 



Fig. 2 e. The same enlarged, showing more distinctly the triangular cup and the sutures of the 

 plates. 



Fig. 2 f. Lateral view of the same specimen. 



Fig. 2 g. The plates separated, showing the structure of the crinoid as far as the first divisions 

 of the arms. 



Fig. 2 h, i. A costal and arm-joint enlarged, showing the character of the surface markings. 



Fig. 2 ^. A fragment of a column, composed of irregularly alternating thicker and thinner 

 plates, which are also interrupted, or not continuous laterally, each joint being often 

 composed of several pieces overlapping each other. The surface is ornamented in the 

 same manner as the plates of the cup ; the crenulations upon the articulating sur- 



[PALiEONTOLOGY VoL. II.] 26 



