87 



mils of the costal plates, are of a form similar to those of Poteriocrinites,and hare 

 also above a horse-shoe-like impression, with a transverse, perforated ridge, on 

 which is inserted the first arm joint (fig. 10. and 11.) to which the cuneiform 

 joint of the arm articulates. 



The HANDS. Several horse-shoe-shaped joints (12. to 13. fig. IB. to 19.) 

 closely resembling those of Pentacrinus Caput Medusae, articulate and arrange 

 in two series on the cuneiform joint. Each series has at its summit a cuneiform 

 joint, from whose upper angular portion the two first series of a double hand 

 set off, interrupted again by a cuneiform joint, from which a finger and a second 

 series of hand joints proceed, terminated by another cuneiform joint which 

 supports two fingers. Each hand, as far as I could ascertain, has six fingers, 

 the whole number of them, therefore, amounts to sixty; they are all tentacu- 

 lated at alternate sides, and resemble those of Pentacrinus Caput Medusae. 



An hexagonal or heptagonal plate generally interposes between the sca- 

 pulae where the truncated costal occurs, from which the integument, protected 

 by calcareous plates, extends over the abdominal cavity and sulcy in the arms 

 and hands. In a specimen in the Ashmolean collection at Oxford (fig. 29. 30.) 

 this integument is swollen out, and gives the specimen a singular appearance. 



The base of the column terminates in a fasciculum of muscular fibres. 



A specimen has occurred to roe, where the columnar joints (fig. 22. to 24.) 

 are alternately smaller and larger. I am not aware whether it possesses suffi- 

 cient character to be considered a variety of the former species. 



