Fig. 5. Cyathocrinus geometricus. a, b, c, d, e. 

 (I. — lateral aspect. 



b. — view of the vertex. — Mr. Austen's specimen. 

 c. — dorso-central view, 

 (/.—ray-bearing plate. 

 e. — perisomic plate of the first series. 



Fig. 6. Cyathocrinus!' pinnatus. a, b. 

 a. — rays, tentacula, &c. 

 b. — column and bifurcating; side arms. 



Fig. 7. Cyathocrinus bursa, a. 

 a. — dorso-ceatral asi)ect. 



Fig. 8. Cyathocrinus mammillaris. a, b. 

 a. — lateral aspect. 

 b. — lateral aspect of a smaller specimen. 



PLATE VIII. 



Fig. 1. Cyathocrinus conicus. a, b. 

 a. — lateral aspect. 

 b. — lateral view, shewing the meso plate between the rays. 



Fig. 2. Cyathocrinus calcaratus. a, b, c, 

 a. — dorso-central aspect. 

 b. — lateral aspect shewing the meso plate. 

 c. — lateial view of a smaller specimen, exhibiting the excavation for the rays. 



POTERIOCRINUS. 

 Fig. 3. POTERIOCRINUS CRASSUS, a, to 111. 



o. — lateral aspect shewing the column, rays, &c. 



b. — the same specimen reversed, shewing the base of the oral tube. 



c. — specimen on which Miller founded the genus. 



d. — specunen exhibiting the bifurcation of the rays and a portion of the oral tube. 



e. — small specimen shewing the arrangement of the intermediate plates. 



J'. — exhibiting the manner in which the rays bifurcate. 



(J. — articulating facet of columnar joint. 



h. — portion of injured column, exhibiting marks of reparation. 



i. — enlarged columnar joints, similar to the preceding. 



k. — columnar joint, with large canal. 



rr>. — columnar disk. 



