PLATE XIll. 



PAGE 



Figs, la, lb. Myliobatis magister Leidy 100 



la. Transverse surface of the same siieciiuen shown in Plate XII, 



Fig-. 3. The anterior end is placed upj)erniost in the fig-nre. 

 lb. Attached surface of same specimen. 



Figs. 2a, 2b. Myliobatis copeanus Clark 99 



2a. Transverse section. Liverpool Point. 



2b. Attached surface, same locality. The anterior end is placed ux^per- 

 most in the fig-ures. 



Figs. 3a, 3b. Aetobatis aecuatus Agassiz 102 



3a. Attached surface of detached tooth. Popes Creek. 

 3b. Lateral aspect of same specimen. 



Fig. 4. Myliobatis sp 101 



Transverse and longitudinal vieAvs of caudal sjaine, Ashley Eiver, S. C. 

 Museinn Comp. ZooL, Cambridge. 



Fig. 5. Myliobatis sp 101 



Transverse and lougitudinal views of caudal spine, Montgomerj', La. 

 Museum Comp. ZooL, Cambridge. 



Figs. 6, 7a, 7b. Myliobatis coPEAis^rs Clark 99 



6. Nearly perfect uiDper dental plate of a comparatively young indi- 

 vidual; the anterior end shown uppermost in the figure. Clifton 

 Beach. 

 7a. Oral surface of lower dental plate of a comiiaratively 3 oung indi- 

 vidual A-sath serrated sutures due to wear. Clifton Beach. 

 7b. Inferior aspect of same specimen. 



Fig. 8. Aetobatis arcuatus Agassiz 102 



Oral surface of a detached tooth. Popes Creek. 



