PLATE LI. 



Page 



Pekiechocrinus Whitfieldi (Hall) 522 



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



2(7. Side view of the dorsal cup. (After Hall.) 



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



3. Posterior view of a large elongate specimen. 



4. Ventral aspect of another specimen. 



Periechocrinus maecouanus (Winch, and Marcy) 523 



Side view of the dorsal cup. 



Periechocrinus tenuidisccs (Hall) 531 



6. Antero-lateral view of the dorsal cuj). 



Periechocrixus orxatus (Hall) 527 



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



Megistocrixus xobilis W. and Sp 537 



8. A young specimen. (Type of Megistocrinns parvus^ 



Perieciiocrisus Whitei (Hall) 530 



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



group. 



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



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



