PLATK XX— Continned. 



ANOPLIA; SUB-GEN. NOV. 

 Page 309. 



Anoplia nucleata, Hiill. 



(See Plat« XVIIa, figs. 17, 18.) 

 Fig. 14. Internal cast of a pedicle-valvfi ; .shciwing thft impression of the .short median septum, and the pus- 



tulose character of the pallial region. X 3. 

 Fig. 15. The interior of a brachial valve ; showing the muscidar impression and the pustulose surface. 



The cardinal process is hilobeil, but is probably shorter than is noi-raal for the species. X 3. 

 Fig. 16. The exterior of the brachial valve; showing the smooth surface. X 3. 



Oriskany sandstone. Jones ccmnty, lU'mins. 

 Fig. 17. The central cardinal portion of an internal cast of the jiedicle-valve ; showing the filling of the ob- 

 li(Hie carilinal tubes which do not peneti-ate to the external surface. X 6. 

 Oriskany sandstone. Columbia county, N. Y. 



CHRISTIANIA. gen. nov. 



Page 398. 

 Chkistiania SUBQUADRATA, Hilll. 

 (See Plates XV and XVIIa.) 

 Figs. 18, 19. Two views of the pedicle-valve ; showing its elongate form, incurvature and smooth or squam- 

 ous exterior. X 2. 

 Fig. 20. The exterior of the brachial valve, which shows the cardinal process and edges of the crural 

 plates. X 2. 



Lower Helderberg group. Perry county, Tennessee. 



LEPT^NA, Dalman. 



Page 276. 



Lept.«na rhomboidalis, Wilckeus. 



(See Plates VIII and XVIIa.) 

 Fig. 21. The deltidial area of both valves of a small individual. X 3. 

 Fig. 21a. Longitudinal section of the two valves; showing the degree of curvature. 



Fig. 22. The intei-ior of a br.achial valve ; showing very di.stinctly the division into anteiior and posterior 

 muscular scars. 



Hudson River gi-oup. Cincinnati, Ohio. 

 Fig. 23. The interior of a brachial valve, in which the margins of the broad posterior adductors have be- 

 come elevated into free alate extensions. X 2. 

 Niagara group. Waldron, Indiana. 

 Fig. 24. The muscular ai'ea of the brachial valve, figured on Plate VIII (fig. 31) ; enlarged from a gutta- 

 percha impression. The aiea is subdivided into three pairs of scars, the elongate central pair 

 being probably accessory to the posterior adductors. X 3. 

 Waverly group. Medina county, Ohio. 



Leptjina ? unicostata, Meek and Worthen. 



See Plate XVIIa, fig. 39. 



Figs. 25, 25a. The interior of a brachial valve and cardinal area of a pedicle-valve ; showing characters of 



LEPT.aNA. 



Hudson River group. Ohio. 



STROPHOMENA, Rafinesque (de Blainville). 



I'age i4.'i. 



Stropiiomena Winciielli, sp. nov. 

 (See Plate IX, fig. 12.) 

 Fig. 26. An enlargement of the muscular area of the brachial valve cited ; showing the broad posterioi- and 

 elongate anterior seal's. X 3, 



Trenton limestone. Janesville, Wisconsin. 



