DESCRIPTION OF 



PLATE VIII. 



Fuse 



Fig. 1. PLATYCRINUS CAVUS. 527 



1 a. The calyx in profile. 



1 b. View of the base, natural size. 



"Fig. 2. PLATYCRINUS POCILLIFORMIS. 528 



2 a. View of the base. 



2 b. Profile, showing elevation, form of first radial plates, and cicatrix for 



the attachment of the second radial. 



. 

 Fig. 3. PLATYCRINUS PILEIFORMIS. 529 



3 a. View showing the elevation of the basal plates, the first radial plates, , 



with the base of one pair of arms attached. 



3 b. Basal view of the same specimen : the two lower radial plates of the 

 figure, and the radial on the left side, are represented as too protube- 

 rant. 



- 



Fie. 4. PLATYCRINUS WORTHENI. 530 



o 



4. A specimen preserving the base, with two of the radial plates, and the 



arms of two series nearly entire. 



Fig. 5. PLATYCRINUS SHUMARDIANUS. 532 



5. Lateral view, showing the cup with fragment of column, the edges of 



the concave base, the radial plates and arms which are somewhat bro- 

 ken and distorted. 



Fig. 6. PLATYCRINUS PLANUS ? 533 



6 a. Lateral view, showing form of cup on one side, radial plates with 

 points of attachment to arm-plates, interradials, and plates of the 

 summit. 



6 b. View of the opposite side, showing similar features in the lower plates, 



with some remains of the arms above. 



Fig. 7. PLATYCRINUS TUBEROSUS. 534 



7 a. Anal and postero-lateral view, showing the incurved upper margins 



of the radial plates, the bases of the arms, and the plates of the sum- 

 mit with the anal opening. 



7 b. View of the base of the specimen, showing the basal, radial, and first 



arm-plates, with the interradial plates. 



' 



Fig. 8. PLATYCRINUS DISCOIDEUS. 535 



8 a. Basal view of the specimen. 



8 b. Profile view, showing the elevation of the side of the cup. 



Fig. 9 & 10. PLATYCRINUS SUBSPJNOSUS. 536 



9. View of a small specimen, showing the base and first arm-joints. 



10. Profile view, showing the surface of attachment for the second arm- 

 plates, the anal aperture, and the spiniform extension of the plates. 



Fig. 11. PLATYCRINUS SCULPTUS. 536 



11. Basal view, showing the depressed area for attachment of column, form 

 of plates and surface ornaments. [The nodes are often more confluent 

 than shown in the figure.] 



[ IOWA PLATES.] 2 



