54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 65 



PLICATOCRINHLE 



Calyx 



1. Calyx in the form of a cup, protecting the visceral mass dorsally 

 and laterally. 



1. Basals present. 



1. Five basals (minority). 



2. Three basals (majority). 



1. Basals separate (majority). 



2. Basals fused into a single calcareous element (minority). 



2. No infrabasals. 



1. Five radials. 



2. Interradials absent. 

 2. Anal x absent. 



1. Interbrachials present. 



Column 



1. Entire column present. 



1. Column jointed. 



1. Column composed of short cylindrical columnals with radial 



crenellse. 

 1. Column composed of a single type of columnals, without a proxi- 



male or nodals. 



1. Column terminating in an expanded terminal stem plate. 



2. Radicular cirri absent. 

 1. Cirri absent. 



Disk 



1. Disk entirely covered with plates. 



1. Orals present. 



1. Orals of different sizes. 



2. Orals a spherical triangle (minority). 



1. Orals with upturned inner edges (majority). 

 1. Mouth central. 



Arms 



1. Arms composed of a linear series of ossicles, without IBr 



series (majority). 



2. Arms dividing one or more times, without IBr series (minor- 



ity)^ 

 1. The first bifurcation is at a more or less indefinite distance from 



the second post-radial ossicle. 

 1. A suture between the first two post-radial ossicles. 



