CALYPTOCRINID^, 



Monocyclic. Lower brachials and interbrachtals forming am important part 



OF THE DORSAL CUP. RaDIALS IN CONTACT ALL AROUND. ArMS RESTING IN 

 COMPARTMENTS, FORMED BY PARTITIONS ATTACHED TO THE TEGMEN. PlATES OF THE 

 CALYX LIMITED TO A DEFINITE NUMBER. DORSAL CUP, EXCEPT THE BASE, PERFECTLY 

 PENTAMEROUS. 



Analysis of the , Genera. 



Basals 4. 



1. Partitions extending to the tips of the arms .... 



2. Partitions enclosing only the lower ^portions of the arms 



eucalyptoorinus. 

 Callickinus. 



Geological and Geographical Distribution, 

 Number of known species. 



(Open figures indicate American ; tliose marked ( ), European.) 



EORMATION. 



Calyptocrinid^. 



General. 



American. 



Approximate 



European 



Equivalents. 



Eucalyptocrinus. 



Calliorinus. 



Devonian. 





Eifel. . 



(1) 





Upper Silurian. 



Niagara. 



Wenlock. 

 Gotland. 



17 (10) 



4 (8) 



f 21 

 Total species 40 j ..^^. 



17 (11) 



4 (8) 



EemarJcs. — Roemer proposed the family name '' Eucalyptocrinidge " 

 (Lethsea Geognos. (Ausg. 3), 1855, p. 229), which Angelin in 1878 changed 

 to Calyptocrinidae. The latter name was accepted by Zittel, who errone- 

 ously included with it Lyriocrinus Hall, which is a dicyclic Crinoid. 



The Calyptocrinidae agree substantially with the Dolatocrinites section of 

 the Melocrinidae in the construction of the dorsal cup, but their basals occupy 

 the bottom of a deep concavity, and they are remarkable for having the 



