PLATE LXIII. 
(Figures 1-3, 8-16, 21-28, 30, 33-36 by G. 1^. Si.mpson; 4-7, 17-20, 29, 37, 44 by E. Emmons; 31, 32 by F. B. Meek; 38-13 
by H. B. Whitfield ) 
Gknus PARA8TROPHIA, gen. nov. 
Page 221. 
Parastrophia hemiplicata, Hall. 
Figs. 1,3. Dorsal and front views of an average specimen ; showing the elevation of the plicated fold. 
Fig. 2. Cardinal view of an internal cast; showing- the median septa and spondylia of both valves. 
Trenton limestone. Jacksonburgli, N. Y. 
Parastrophia divergens, sp. nov. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. 
Ventral view of an average specimen, somewhat worn in the umbonal region, exposing the sjion- 
dylium and supporting septum. 
Front view ; showing the elevation of the median fold and the low, sparse plication. 
Dorsal view of the same specimen, which has been so worn at the beak as to expose the convergent 
walls of the spondylium. 
Cardinal view of a specimen transversely sectioned in the umbonal region ; showing the spondvlia. 
In the shallower or pedicle-valve the median septum is very low and scarcely apparent, while 
in the brachial valve the lateral walls of the spondylium, in this section, rest upon the bottom 
of the valve. The crural plates arising from this spondylium are also shown. X l-j. 
Hudson Rivei- group. Wilmington, Illinois. 
Parastrophia reversa, Billing.s. 
Figs. 8, 9, 10, 14. Ventral, profile, dorsal and cardinal views of the exterior of an average example ; showing 
the i-elative convexity of the valves and the character of their 23lication. 
Fig. 11. Cardinal view of a sjiecimen which has been transversely sectioned in the umbonal region, the 
brachial valve being represented below ; showing the spondylium of the jiedicle valve sup- 
]iorted by its median sejitum, and the sejital plates of the brachial valve resting on the bottom 
of the shell and supporting the ci-ural ajiojihyses. 
Figs. 12, 13. Dorsal and ventral views of a smaller siiecimen ; showing the tine concenti-ic lineation of the 
surface. 
Clinton horizon. Island of Anticosti. 
Parastrophia multiplicata, sj). iiov. 
Figs. 15, 16. Anterior and iirotile views of an internal cast; showing- the broad, strong-'idications of which 
there are four on the median fold and three in the sinus. 
Fig. 21. Cardinal view of another individual; showing the casts of the siiondylia of the two valves, in the 
brachial valve the lateral walls having rested ujion the inner surface of the shell.' The mus¬ 
cular scars of the brachial valve are also i-etained. 
Niagara dolomites. Newr Milwawkee, Wisconsin. 
Parastrophia Greenii, sp. nov. 
- Figs. 17, 18, 19, 20. Ventral, lu-ofile, dorsal and cardinal view of an intern-d cast; showing the character of 
the plication of the surface, and the median septum of each ^'alve. 
Fig. 22. Cardinal view of another and rather more convex internal cast; showing the cavities left by the 
• median sejita. 
Niagara dolomites. Near Milwaukee, Wiscomhi. 
Parastrophia lattplicata, sp. nov. 
Fig. 23. An intei-nal cast of the brachial valve ; showuig the few broad jilications and the cavity of the 
median sejitum. 
Fig. 24. An internal cast of the brachial valve in which the tilling- of the sj^ondylium is exiiosed and the 
four scars of the adductor imjjression distinctly retained. 
Figs. 25, 26 Cardinal and ju-ofile views of the same siiecimen. 
Fig. 27. Anterior view of a siiecimen ; showing the elevation of the median fold, and the character of the 
jilication. 
Niagara dolomites. Near Milwaukee, Wiscon.sin. 
The original specimens of this and the two ju-eceding species are from the collection of Thomas A. 
Gkeene of Milwaukee. 
