EXPLANATION OF PLATE X. 



{Figures all of natural size.) 



Cyrtiiia '.' Curupiraj Rathbun, sp. nov., page 243. 

 1 and G. Dorsal valves. 



Retzia Wardiana, Hartt, sp. nov., page 345. 



3, 4, 5, 8, 11, 13 and 14. Ventral valves. 



16. Ventral valve, with the plications finer and more numerous than in the 

 majority of specimens. 



3 and 9. Dorsal valves. 



Orthis Nettoana, Rathbun, sp. nov., page 247. 

 7 and 13. Ventral valves. 

 10. Dorsal valve. 



Terebratula Derbyaiia, Hartt, sp. nov., page 23(5. 

 15, 18, 34 and 35. Ventral valves. 



17, 19, 21 and 23. Dorsal view of specimens of which both valves are 



preserved. The beaks of the ventral valves are seen extending 

 beyond the dorsal valves, but in all the specimens they are more <»r 

 less defective. 

 30. Dorsal valve. 



Tropidoleptns cariiiatiis, Von., (sp.,) page 354. 



26. Exterior mould of dorsal valve, very much broken. 



Ket/Ja Jaiuesiana, Hartt, sp. nov., page 343. 



29, 33, 34, 36, 37 and 38. Ventral valves, (^bowing the enlarged uu'diau 



depression. 

 37, 38, 31, 33 and 85. Dorsal valves. 



30. View of dorsal valve of a specimen in which both valves are ])re- 

 served. The beak of ventral valve is slightly extended Ix-yoiul the 



•• dorsal valve. 



33. Dorsal view of a rather narrow specimen, of which tlie vential valve 

 is also preserved. The plications are less in uuiul)ci- tluiu usual. 



Clionetes H(U'bort-Smithii, Hartt, sp. nov., page 351. 



39, 41, 42 and 46. Ventral valves of ordinary size. 



44. Ventral valve, same as above, but smooth fi-oiii tlic clianactcr of the 

 rock in which it occurred. 



40. Ventral valve, rather above the average size. 

 45 and 47. Exterior moulds of dorsal valves. 



Clioiiotes Oiiettiaiia, Rathbun, sp. nov., page 353. 



43 and 48. Ventral valves, with nearly smooth surfaces and showing the 

 short median septum very distinctly. 



(Except where otherwise stated, the above specimens are all of interior 

 moulds.) 



