

II. 



CRINOIDEA SEMIARTICULATA. 



Character of the Division. 



J. HE plate-like joints resting on the superior columnar joint, and forming 

 the cup containing the viscera, articulate by transverse processes, having a mi- 

 nute central perforation. 



Observation. 



Although I am acquainted with but one species strictly possessing the cha- 

 racter assigned to it (viz. that which serves me as the type for the genus 

 Poteriocrinites) yet I thought it advisable to constitute the division SEMIAR- 

 TICULATA, to mark in a more conspicuous manner the transition from regularly 

 articulating joints to plates adhering only by muscular sutures. 



