EXPLANATION OF PLATES 375 





Plate 22. — Manlius Limestone Fossils, Erie County, New York 

 ( All are enlarged X 2| except figure 16, which is enlarged X 3J ) 



Page, 



Figure la-c. Orthothetes hydraulicus (Whitfield) .' 365 



la. View of the brachial valve, with the hinge area of the pedicle 

 valve, showing deltidium. 



16. View of the same from above, showing hinge areas of both 

 valves, the strong deltidium of the pedicle valve and the bifid 

 cardinal process and band like chilidium of the brachial valve. 

 (X3J.) ' 



lc. View of the interior of a smaller pedicle valve, showing cardinal 

 teeth and dental plates. 



(All are drawn from gutta-percha casts) 



Figure 2a-d. WhUfieldella sulcata (Whitfield) 367 



2a. View of a pedicle valve, showing the mesial sinus. The spec- 

 imen also shows old age characters. The shell is retained in 

 this specimen. 



26. Another specimen showing brachial valve and the cardinal 

 slopes of the pedicle valve. The foramen and delthyrium are 

 somewhat imperfect. 



2c. Lateral view of a specimen. 



2d. Dorsal (brachial) view of the same. 



(2b-2d are drawn from gutta-percha casts and are slightly re- 

 stored) 



Figure 3a-6. WhUfieldella cf. rotundata (Whitfield) 368 



3a. View of a pedicle valve, the shell having been dissolved and 

 the mold of the exterior impressed on that of the interior. 



36. Side view of same, showing position of dental plates. 



Figure 4a-d. WhUfieldella cf. Ixvis (Whitfield) 369 



4a. Internal mold of pedicle valve, showing impressions of dental 

 plates. 



46. Side view of same. 



4c. Cast of same in gutta-percha, showing cardinal teeth and dental 



plates. (The drawing is foreshortened.) 

 4d. Another internal mold of a pedicle valve, showing impressions 



of dental plates and median septum. 



(4c is drawn from a gutta-percha cast) 



