Nov., 1918] Structure of A gelacrinites and Streptaster 83 



DESCRIPTION OF PLATES. 



Plate I. 



Fig. 1. Specimens of Agelacrijiites attached to Dystaciospongia Madisoniensis. 



Coll. W. H. Shideler, Fallen Timbers Creek, Indiana. X. I. 

 Fig. 2. A gelacrinites cincinnatiensis showing the effect on the peripheral rim of 



crowding against a Lichenocrinits. Dyer coll. X 3. 



Also shows the hydropore (?) between two plates near arm 5. 

 Fig. 3. Agelacrinites pileus to show the outer smaller plates of the peripheral 



rim. X 4. 



Fig. 4. Agelacmiites pileus with peristomial Plates L and R in position and P 

 dropped out. Seen from above. X 4. 



Fig. 5. An Agelacrinite having long cover plates like those of Streptaster. Possibly 

 is Streptaster. 



Fig. 6. Edge view of the same A. pileus photographed in Fig 4., showing the 

 thickness of the median edges of the special peristomial Plates L. & R. 

 X4. 



Fig. 7. Aboral side of an Agelacrinites pileus with flooring plates dropped out and 

 with the arrow indicating the narrow food groove on the aboral side of 

 the cover plates of one arm. X 4. 



Plate II. 



Fig. 8. Agelacrinites cincinnatiensis showing the cover plates of the outer and 

 inner series for almost the whole extent of their length on a part of 

 food groove 1 as cleaned. Dyer coll. X 2.5. 



Fig. 9. Agelacrinites cincinnatiensis showing food grooves 2 and 3 with the 



peristomial region. McCord Coll. X 2.5. 

 Fig. 10. Agelacrinites pileus showing the single cover plates of the food grooves 



and the inter radial plates. Dyer Coll. X 3. 



Fig. 11. Fragment of A. cincinnatiensis showing especially the numerous rows of 

 large plates in the inner part of the peripheral rim, and the cover plates 

 of one side of the distal end of a food groove. W. H. Shideler Coll. X 3. 



Fig. 12. Aboral views 'of two specimens of Agelacrinites austvii var lawshe. Upper 

 specimen shows the detailed aboral view of the posterior peristomial 

 plate. 

 Lower showing in part peristomial chamber and the oral view of a flooring 

 plate of a food groove. X 3. 



Plate III. 



Fig. 13. Camera diagram oral view of all plates (disc, peripheral ring, margin) of 



a specimen of Agelacrinites auslini (Foerste) from Dutch Creek. W. H. 



Shideler Coll. Anal pyramid plates put in from another specimen. X 5. 

 Photograph of specimen diagrammed in Fig. 13. X 4. 

 Agelacrinites to show anal pyramid. Dyer Coll. X 4. 

 Camera diagram of aboral view of all plates of a speciincn oi Agelacrinites 



austiniivom Cowan's Creek. X 5. 



Photograph of specimen diagrammed in Fig. 13. X 4. 

 Agelacrinites pileus showing anal pyramid with plates separated, leaving 



a rectal space. McCord Coll. X 4. 

 Fig. 19. Possibly Streptaster reversata Foerste. Shows peristomial plates and 



anal pyramid closed. McCord Coll. X 4. 



