1888.] natural sciences of philadelphia." 389 



Explanation of Plates. 



Plate XIX. 

 Fig. It: Crotalocrimts rugosus. Ventral aspect of a large specimen 

 from Sweden, showing the inner floor of the calyx, the 

 lanceolate areas, and the outstretched arms with their deep 

 ventral grooves, and in places their covering pieces ; the 

 tips of the arms coiled up so as to expose their dorsal face. 

 The covering pieces at the lower right hand corner re- 

 stored from another specimen. 



(Collection of Wachsmuth and Springer.) 



Fig. 1^ Oblique view of a portion of the same specimen, showing 

 the lamellae beneath the overhanging margins of the high- 

 er radials. 



Fig. It Ventral view of a portion of the arms enlarged. 



Figs. 2f:^ Diagramatic figures showing the arrangement of the high- 

 er radials in Crotalocrinus rugosus ; 2!: the dorsal side ; 2^ 

 the ventral side ; 21 a vertical section through the dotted 

 line in 2^. The numbers refer to the same plates in all 

 three figures, i. e. IL and i!_ to the first and second prima- 

 ry radials, 2L to the secondary radials, 3!_ and 3!_ to the 

 tertiary radials, 4l_ and 4!_ to the quaternary radials; 

 the succeeding plates are brachials. 



Fig. 3. Ventral aspect of the same species from a specimen in the 

 National Museum of Stockholm, showing the rigid cover- 

 ing jjlates around the margin of the calyx. 



Fig. 4. A portion of a first primary radial of the same species with 

 the higher radials in place resting upon it. 

 (Collection of Wachsmuth and Springer.) 



Fig. 5. Enlarged view showing the markings on the lower face of 

 a fii'st radial of the same species. 



Fig. 6. Radials and lower arm plates in Fterotocrinus. 



Fig. 7. The radials and lower arm joints in 3farsupiocrimis ten- 

 nesseensis. 



Plate XX. 



Fig. Vt Crotalocrinus pulcher. Anterior view of a specimen with 

 arms from Gothland, Sweden. 



(Collection of Wachsmuth and Springer.) 



