PLATE LI. 



Page 



Pekiechoceinus Whitfieldi (Hall) 522 



Fig. 1. A very large and unique specimen with arms. 



2a. Side view of the dorsal cup. (After Hall.) 



2b. The plates of one ray, showing ornamentation. (After Hall) 



3. Posterior view of a large elongate specimen. 



4. Ventral aspect of another specimen. 



Periechocrinus makcouanus (Winch, and Marcy) 523 



Side view of the dorsal cup. 



Periechocrinus tenuidiscus (Hall) 531 



6. Antero-lateral view of the dorsal cup. 



Pekiechoceinus oenatus (Hall) 627 



7. Side view of the calyx ; from St. Paul, Ind. 



Megistoceinus nobilis W. and Sp 537 



8. A young specimen. (Tj'pe of Megistocrinus imi'vus.) 



Periechocrinus Whitei (Hall) 530 



9. Anterior view of a large specimen with arms from the Lower Burlington 



group. 



10. A specimen from the Kinderhook group of Marshall Co., Iowa. 



(All specimens, except 2a and h, in the collection of Wachsmuth and Springer.) 



