Fig. 2. POTERIOCRINUS QUINQUANGULARIS. a, b, C, d, e. 



2, a. — lateral view of two specimens, shewing the arrangement of the plates. 



2, h. — lateral aspect, exhibitmg the intermediate plates, and the pentagonal articulation 



of the column. 

 2, c. — lateral aspect, shewing the rays and a portion of the proboscis. 

 2, d. — enlarged figure of the same specimen. 

 2, e. — a portion of the column with a side arm attached. 



Fig. .3. POTERIOCRINUS CONICUS. a, b, c. 



3^ a. — foreshortened lateral view, shewing the arrangement of the plates, and the radii 



for the attachment of the column. 

 3, b. — vertical view of the same specimen, exhibiting the points of articulation for the 



rays. 

 3, c. — lateral view of a different specimen, shewing the intermediate plates. 



Fig. 4. POTERIOCRINUS LATIFRONS. 



4. — lateral view, shewing the column, rays, &c. 



Fig. 5. POTERIOCRINUS TENUIS, a, b. 



5^ a. — lateral aspect, exhibiting the arrangement of the plates, with the proboscis, 



column and rays. 

 5, b. — enlarged view of the same specimen. 



Fig. 6. POTERIOCRINUS IMPRESSUS. 



6. — lateral view, shewing the arrangement of the plates. 



Fig. 7. POTERIOCRINUS DACTYLOIDES. 



7. — lateral aspect, shewing the rays, &c. 



All the figures in this plate, with the exception of Nos, 5 and 6, are taken from 

 specimens in the cabinet of the Authors. — Figure 5, is drawn from a specimen in the 

 collection of Mr. W. Morgan, to whose liberality we are indebted for this addition to 

 our illustrations. 



