PLATE XX. 



Pleurotomaria rdoulata. 



V&ge 75. 

 Pigs. 1-3. Three views of a si)<>cimen having the shell denuded ; fig-. 2 shows the plicae near the lip. 

 Fijfs. 4. 5. The spii-e of another specimen and ai>ertural view of the same. 

 Fig. 6. Enlargement to two diametei-8 of a specimen with high spire and obliquely compressed volutions. 



The substance of the shell is preserved showing the surface-markings and spiral band. 

 Fig. 7. Enlargement to two diametei-s of a specimen with more ventricose volutions and shorter spire, pre- 

 ' serving the spire and having a proportionally wider band. 



Pleurotomaria Itts. 



Page 76. 

 Pig. 8. A large specimen almost denuded of sheU, but indicating surface-markings on the upper volutions 



an<i remains of the spiral band on the last volution. From near Bellona, N. Y. 

 Figs. 9, 10. Two views of an internal cast. From Cumberland, Md. 

 Pigs. 11, 12. Two views of a partial cast retaining traces of the surface characters toward the aperture. 



From western New York. 

 Fig. 13. A cast showing only the remains of the spiral band. From Canandaigua Lake. N. Y. 

 Pig. 14. A sjwcimen preserving the surface characteis in remai-kable perfection. From Pratt's Falls, near 



Pom[)ey, Onondaga county, N. Y. 

 Fig. 15. A large, well-iii-eserved specimen retaining the surface characters. From York, Livingston 



county, N. Y. 

 Fig. 16. Enlargement of a part of the body-volution of the specimen figure 11. 

 Fig. 17. Enlargement of a part of the body-volution of fig. 15, showing some differences in the strength and 



character of the markings from those of fig. 16. 



Pleurotomaria capillaria. 



Page 77. 

 Figs. 18, 19. A specimen enlarged to two diametei-s, of usual form and size. From the Hamilton group, 



Madison county, N. Y. 

 Fig. 20. Enlargement (two diameters) of a specimen, preserving the upper volutions, and showing surface 



charactei-s different from the preceding. From the soft shales of the Hamilton group, Norton's 



Landing, east side of Cayuga Lake, N. Y. 

 Pig. 21. Enlargement to two diameters of a specimen which differs in surface characters from the preceding. 



From the same locality. 



Pleurotomaria Ella. 



Page 72. 

 Kga. 22-25 The opposite sides, summit and basal views of a specimen which exhibits the surface characters 

 very perfectly. It has probably been somewhat compressed vertically, flattening the volutions, 

 but not materially altering the form. 



Pleurotomaria filitkxta. 



Page 73. 



Vig. 96. The side of a flattened specimen with surface characters very beautifully preserved. The trans- 

 verse striffi are too coarse in the figure, and the revolving striae should be entirely subor- 

 dinate. 



Pig. 27. The opjKwite side of the same specimen, having a part of the outer volution broken away revealing 

 the columella and umbilical callus. 



