The Etymology of the names adopted will be found in the description of each genus and species. 



I. DIVISION. ARTICULATA. Joints forming the supe- 

 rior cup-like body of the animal articulating to 

 each other. 



A Pelvis formed of five joints. 

 3 Supporting five costal joints. 

 a Column enlarging at the summit. 



a Fingers formed of a single series of joints. I. GEN. APIOCRIIUTIS. 



* Column round 



o Alimentary canal round. 



Articulating surface of columnar joints radiated. 1 Sp.rutunJus. 

 ** Column elliptic. 



o Alimentary canal round. 

 Articulating surface of columnar joints trans- 

 versely ridged. 2 Sp. eilipticus. 

 b Column not enlarging at the summit. 

 * Fingers formed f a single series of joints. 

 *** Column pentangular, 

 o Alimentary canal round. 



Articulating surface of columnar joints petal- 

 shaped. IHGEN.PENTACIIJUTES. 

 t Auxiliary side arms round. 

 | In single series. 

 [| Column smooth. 



1 Columnar joints generally alternately 



smaller and larger. 1 ftp. Caput Medusae, 



S Columnar joints generally of more 



uniform thickness. 4 Sp. Basaltiformi*. 



H [| Column tuberculated. 5 Sp. tuberculatut. 



J J Auxiliary side arms in double series. 



|| Column smooth. 3 Sp. subangularit. 



ft Auxiliary side arms angular. 



I Auxiliary side arms in single series. 



H Column smooth. c Sp. Briareut. 



