EXPLANATIOK OP PLATE XVI. 



Gyeodes pktrosa Morton (p. 127). 



Figs. 1-3. Back, front, and enmmit views of a specimen from MuUica Hill. Am. Mus. Nat. Hist., 

 New York City, 

 4. Summit view of ii casi from Crosswicks Creek. Columbia College. 



Gykodks crenata Conrad (p. 126). 



5, 6. Two views of the type specimen from the Acad. Nat. Sci. Phila. 



Gyrodes altispira Gabb (p. 128). 



7,8. Front and back views of a cast from MuUica Hill in the Am. Mus. Nat. Hist., New 

 York City. 



Gyrodes obtosivolva Gabb (p. 129). 



9, 11. Views of different specimens from Upper Freehold. 



12. View of another oast in the collection of the Am. Mus. Nat. Hist., New York City, from 

 New Egypt, New Jersey. 



LUNATIA Halli Gabb. (p. 130). 



13, 14. Two views of a specimen from Mullioa Hill in the Acad. Nat. Sci. Phila. 



15, 16. Similar views of a cast from the same place in the Am. Mus. Nat. Hist., New York City. 



Amauropsis punctata Gabb (p. 132). 



17. View of the type specimen. Acad. Nat. Sci. Phila. 



18. Enlargement of the surface. 



19-21. Views of different individuals showing but slight diversity in form. 



Amauropsis Mebkana Whitf. (p. 131). 



22, 23, 25. Views of different specimens showing a slight difference in form. Pig. 22 enlarged to two 

 diameters. 

 24. Enlargement of the surface. 



Amauropsis paludin^eormis H. M. (pp. 131, 132). 



26. Enlarged view of the type of this species for comparison, two diameters. Am. Mus. Nat. 



Hist., New York City. 

 330 



