53 



supporting a wider hexagonal piece which is twice as wide as high and 

 rests on tlie flat upper side of the tetragonal piece and on one of the 

 sloping sides of each adjoining' radial. The two outer radials of the 

 anterior side are hexagonal, are larger than the middle one, extend 

 mid-height of the second middle radial piece and are proportionately 

 wider than the first middle piece. At the upper end of each of these 

 outer radials is a wide middle face which supports the first arm piece- 

 of that ray, and two sloping sides, one partly supporting the second 

 middle radial i)iece of the anterior side and the other a plate of the 

 posterior side. The radial series of the posterior side are somewhat 

 obscure ; but four plates forming two radial (or a radial and an anal) 

 series can readily be made out. The lower plates do not extend quite 

 as low as the anterior radial series, and are subtrigonal with the angle 

 adjoining the base of the anterior series truncated, which truncation 

 with the free portion of the adjoining anterior radial forms a notch in 

 which the corner of the united basals plays in doubling itself back on 

 the i)Osterior surface of the cup. The upper plates of the posterior 

 radial (and anal) series are hexagonal ; one side resting upon its fellow, 

 one on the sloping side of the adjoining r-adial of the anterior side, one 

 abutting on the first arm piece of the adjoining anterior arm, one 

 carrying a plate of the next series (arm or ventral tube), one abutting 

 its twin posterior radial (or anal), and one whose relations are not 

 made out. I do not find any line of junction between these plates and 

 the basals nor any collection of small plates there although such may 

 exist. Prof. Ulrich calls the posterior radial and anal plates the 

 ventral arch in which he finds three plates in his GremacrinUs pu7ictatus 

 and eight in his proposed genus Halysicrinus, but in both the species of 

 C'alceocrinus, herein described, there are four plates arranged as above 

 stated. 



Each of the arms consists of a primary and a secondary series of 

 plates. The primary series consists in the middle arm of the anterior 

 side of three plates, and in the others of two ; the uppermost in all cases 

 being an axillary piece. The secondary series of each arm is composed 

 of rounded ])icces, longer than wide, bearing pinnules or armlets on 

 alternate sides, beginning on the outside. The pinnules are slender, 

 but their joints are equal in length to the corresponding arm-joints. 



