176 SYNOPSIS OF THE CHARACTERS OF THE 



PlATYCEINUS GBAinJLATUS. Mill. 



Platycrimis granulatus. Mill. Hist. Crin Platycrinus granulatus. Phil. Geol. York. 



Sp. Ch. — Scapular articulation very small ; scapular and pelvic plates having several irregular rows of small, 

 roimded, tubercles. 



Tills beautiful species is very rare ; the few specimens which have occurred are easily recognized by the 

 distinctly tuberculated plates, and minute articulation of the scapulje. 



Platycrinus interscapulaeis. Phil. 



Platycrinus interscapularis. Phil. Pal. Fos. 



SjJ. Ch. — Globose; pelvis saucer-shaped, contracted and produced at the columnar articulation, support- 

 ing five scapulae and one interscapular plate; surface smooth, with few irregularly scattered tubercles. 



In this fine species the large interscapulary plate is very remarkable, resembling in this particular the 

 P. elongatiis. Length from scapular articulation to the columnar adherence one inch two lines, diameter one 

 inch seven lines. 



Platycrinus laciniatus. Phil. 



Platycrinus laciniatus. Pliil. Geol. York. 



Sj). Ch. — Pelvis saucer-shaped, constricted and prominent at the cohmmar articulation; scapulee square; 

 articulation small ; all the plates marked with sharp, very prominent, radiating ridges and tubercles. 



This elegant crinoid is distinguished from the P. ellipticus, P. tuberculatus, and otiier nearly allied spe- 

 cies, by the constricted, neck-hke prominence of the base of the pelvis. 



Platycrinus l^vis. Mill. 



Platycrinus laevis. 31ill. Crin. 



Sp. Ch. — Plates of the body smooth ; scapulse of equal width below and above; each supports an arm 

 having two hands, each of which has two fingers. 



This is not the species figured by Professor Phillips as the P. Icevis of Miller, the figure in the Geol. of 

 York, represents a species with a small pelvis, and the scapulse much narrower below than above, giving a 

 conical appearance to the body ; in the present species, however, the scapulae are equally wide above and 

 below, and the pelvis equal in diameter to any part of the body of the animal. Length of body from scapular 

 articulations four and a half lines, diameter eight lines. 



Platycrinus ornatus. M'Coy. (PI. XXV. fig. 1). 



Sp. Ch. — Pelvis elongate, conical, attenuated, cylindrical at base ; scapulas long, narrow, of equal breadth 

 above and below, each supporting one lengthened, cuneiform arm-joint, having each two hands of great length ; 

 surface of the pelvis and scapulas sculptured with round, curving lines and points ; column near the pelvis com- 

 posed of numerous circular joints, a thicker and longer one alternating with a thinner and shorter one. 



This very curious crinoid is apparently destitute of fingers, tlie hands being of great length, and tentacu- 

 lated to their base ; the scapular plates are beautifully carved in irregular curved lines ; the pelvis has rough- 

 ened, transverse lines, which follow the curves of the scapular articulations ; the produced cylindrical base of the 

 pelvis articulates with a cylindrical column, formed of alternately thicker and thinner joints. Length of body 

 three lines, width two and a half lines. 



