72 



tion and articulation resembles the corresponding: joint of the Pentacrinites. 

 Its length, not unfrequently, exceeds its thickness six times, whence it bears a 

 distant resemblance to a split os humeri of a very small size. 



FINGER JOINT. From its summit proceed the first joints of two fingers, 

 (fig. 24. and 25.) they are equally slender, adhering near the base laterally to 

 each other. On these the following finger joints (fig. 22. and 23.) are inserted 

 in single series, they are much excavated at the inner surface, and by the 

 alternately inclining angle of their superior surface, indicate that the tentacula 

 came oft' alternately from the broader portion of every joint. The specimen 

 in my possession does not display the tentacula, nor have I been able to trace 

 their place of insertion on the finger joints, but I apprehend that these being 

 so thin, and not offering a safe point of attachment, a muscular adhesion 

 existed in this species. I have also found minute plates indicating that the 

 cup-like abdominal cavity, and the excavated sulci in the arm and fingers 

 have been protected by a plated integument, similar to that noticed in other 

 Crinoidea. 



