1885.] NATURAL SCIENCES OF PHILADELPHIA. 363 



Fig. 23. Inner aspect of the calyx of Ichthyocrinus burlingtonensis, show- 

 ing the position of the small nnderbasal. 



Fig. 24. Basals of Pentremites, Bhowing the position of the smaller plate. 



Fig. 25. Basals of Platycrinus, showing the same thing. 



Fig. 26. Basals of Symbathocrinus, showing the same. 



Fig. 27. Column of Poteriocrinus and Cyathocrinus Rarrisi, with radial 

 cirrhi. 



Fig. 28. Column of Belemnocrinus florifer with interradial cirrhi. 



Fig. 29. Column of Cupressocrinus, showing the position of the peripheral 

 canals 



Fig. 30. Column of Ptntacrinus with radial cirrhi. 



EXPLANATION OF PLATE VII. 



These diagrams are designed to show the relation of the summit plates 

 with each other, and with adjoining plates : — 



Fig. 1. Diagram of the pLites in the early larva of Antedon rosacea. After 



Dr. P. H. Carpenter. 

 Fig. 2. Summit plates of Dorycrinus mississippiensis. 

 Fig. 3. Ventral aspect of Eretmocrinus coronatus. 

 Fig. 4. Summit plates of Amphoracrinus spinobrachiatus. 

 Fig. 5. Vential aspect of Platycrinus glyptus. 

 Fig. 6. The same of Platycrinus subspinosus. 

 Fig. 7. The same of Platycrinus Halli. 

 Fig. 8. The same of Platycrinus tuberosus. 

 Fig. 9. The same of Agaricocrinus Wortheni. 

 Fig. 10. The same of a large specimen of Agaricocrinus americanus. The 



dorsal interradials are attached ou three sides. 



EXPLANATION OF PLATE VIII. 



Fig. 1. Internal cast of Strotoerinus regalis, showing the impression of the 

 radiating canals along the inner floor of the vault, and the presence of 

 three summit radials between each proximal. 



Fig. 2. Internal cast of Actinocrinus rhultiradiatvs, showing the same as 

 fig. 1, however, with two summit radials anteriorly and three poste- 

 riorly. (The pentapartite protuberance along the oral plate is too 

 prominent in the figure). 



Fig. 3. Internal cast of a specimen of Teleiocrinus, showing the same as 

 fig. 1. 



Fig. 4. Ventral aspect of Steganocrinus concinnus. 



Fig. 5. Ventral aspect of Meghtocrinus Evansii. 



Fig. 6. Ventral aspect of Platycrinus burlingtonensis. 



Fig. 7. Ventral aspect of Marsupiocrinus Tennessee. 



Fig. 8. Ventral aspect of Batocrinus subwqualis. 



