280 PROCEEDINGS OF THE ACADEMY OF [1881. 



Zittel unites Hahrocrinus, Carpocrinus, Besmidocrinus aiul 

 Leptocrinus under Carpocrinidoe. 



The pinnules in this genus are exceedingly interesting. In 

 some of the species (compare Angelin's figures), we find toward 

 the interradial side the proximal pinnule much larger. It is given 

 off from a second secondary radial, which is converted into a regular 

 bifurcating plate ; it stands more erect than the other pinnules, 

 its lower portions embraced within the bod}' walls, its upper and 

 free parts following the direction of the arms. The construction 

 is such that we cannot doubt these large pinnules form a link 

 between arms and pinnules, which finally in Desmidocrinua became 

 transformed into regular arms. 



Generic Diagnoais. — General form oblong ; calyx short, cj'athi- 

 form ; symmetry'- bilateral 



Basals three, short ; two of them equal, the third smaller by 

 one-balf. Primary radials 3X5; the first larger than the other 

 two ; the second short, qiiadrangular or hexagonal ; the third 

 axillary giving off two, rarely 3 X 10 secondary radials. The 

 latter are rounded at the dorsal side, in form almost resembling 

 arm-joints, but larger, especially higher. The secondary radials 

 support directly the arms, of which there are ten to the entire 

 individual, and these remain simple throughout. 



The arms are long, heav}', cylindrical, tapering at their tips, 

 and are composed of short single joints, with parallel sutures. 

 Pinnules long, thread-like, composed of a great number of joints. 



Interradials from two to three in two series ; the first plate 

 •large, the upper series generally very small and indistinct. Some 

 of the larger species have a third series with their plates decreas- 

 ing in size upward. 



Anal area considerably wider, and composed of many more 

 plates. The first anal plate in line with the first radials, and fully 

 as large and even larger. There are three plates in the second 

 series, somewhat smaller than those of the first, and generally 

 three in each succeeding series, all arranged in longitudinal rows. 



Interaxillary plates from none in the very small species, to one 

 or three in larger ones. 



Vault only partly known. In Carpoci'inus ornatus (Iconogr. 

 Crin., PI. 27, fig 5) it seems to have been composed of a large 

 number of plates, among which the apical dome plates are easily 

 distinguished by their larger size : radial portions covered by 



