EXPLANATION OF PLATE XVIII. 



SCALARIA (Opalia) Thomasi Gabb ? (p. 137). 

 Fig. 1. View of the only specimea of the species observed, Acad. Nat. Sci., Phila. 



SCALARiA SiLLiMANi Morton (p. 138). 

 2. View of the specimen identified. 



SCALARIA? PAUPERATA Whitf. (p. 141). 



3, 4. Two views of a specimen retaining some of the shell. 

 5, 6. Similar views of a complete cast. 

 7. Enlargement of surface from Fig. 3. 



TURRITBLLA COMPACTA Whitf. (p. 142.) 



8, 9. Two views of a cast of this species. 



TURRITELLA GRANULICOSTA Gabb (p. 144). 



10. View of the type specimen. Acad. Nat. Sci., Phila. 



11. Enlargement of the surface. 



ScALARiA? Hercules Whitf. (p. 140). 



12. View of the specimen as obtained from a gutta-percha impression in the natural mold. 



Columbia College. 



TURRITELLA VERTBBROIDBS, MortOn (p. 146). 



13, 14. View of Morton's type and au enlargement of the surface. Acad. Nat. Sci., Phila. 



15. View of au impressiou iu a natural mold from Moumoutb, New Jersey. 



16. View of a large cast in the collection at Columbia College. 



17. View of a cast from Monmouth County, New Jersey. 



18. An imperfect cast, Mr. Gabb's second type of LaMspira lumbricalis, natural size. Acad. 



Nat. Sci., Phila. 



TURRITELLA BNCRINOIDES MortOU (p. 143). 



19,20. View of Morton's type and enlargement of surface. Acad. Nat. Sci., Phila. In the en- 

 largement, the volution is represented as too round. 

 21, 22. View of two internal casts referred to this species from Upper Freehold, New Jersey. 



TURRITELLA LlPPINCOTTl "Whitf. (p. 145). 



23, 24. View of a partial cast from Crosswicks, New Jersey, and an imprint from the natural mold 

 from Holmdel, New Jersey. 



LaXISPIRA LUMBRICALIS Gabb (p. 148). 



25. Copy of Mr. Gabb's figure of the type of the genus and species. The second specimen is 



Fig. 18. See also explanation of Fig. 26. 



SiLIQUARIA PAUPERATA Whitf. (p. 149). 



26. Enlarged view (two diameters) of a cast showing the slit. This specimen was included 



in Gabb's types of Laxispira lumbricalis. 

 27,28. Two views of another specimen found with the above. Acad. Nat. Sci., Phila. 



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