[xviii. ] 



MESODON. 



Fig. 5, 6, 7. M. ALBOLABRis, Say. Nicholson's Encyc, 

 p. 181, t. 1, f. 1, 1816. 

 Say, Am. Concli., t. 13, April, 1831. 

 Binney, Terr. Moll., ii., p. 99, t. 2, 1851. 

 Bland, Ann. N. Y. Lye, vi., p. 359, Sept., 



1858. 

 W. G. Binney, 1. c, p. 43, 1859. No. 10. 



" 8. M. EXOLETA, Binney. l.-c, p. 121, 1. 10, 1851, 

 W. G. Binney, 1. c, p. 54, 1859. 

 H. zaleta, Binney. Bost. Jour. N. Hist., i., p. 



492, t. 20, May, 1837. No. 1. 



" 9. M. DENTIFERA, Binney. Bost. Journ. Nat. 

 Hist., i., D. 494, t. 21, May, 1837. 

 Binney, Terr'. Moll., ii., p. 134, t. 12, 1851. 

 W. G. Binney, 1. c, p. 55, 1859. No. 2. 



" 10. M. Wheatleyi, Bland. Ann. N. Y. Lye. 



Nat. Hist.,vii., t.4,f. 7, Dec, 1861. No. 3. 



" 11. M. Christyi, Bland. Ann. N. Y. Lye. Nat. 



Hist., vii., t. 4, f. 5-6, Dec, 1861. No. 4. 



HELICID^. 



Synonymy and Referekce to 

 Plate 8. 



MESODON. 



Fig. 1. M. THYKOIDES, Saj. Jour. Acad. Nat. Scien- 

 ces, i., p., 123, Oct., 1817, ii., p. 161, Jan., 

 1821. 

 Sny, Nicholson's Encyc, 1818. 

 ' Say, American Conchologv, p. 13, Apr., 1831. 

 Binney, 1. c, p. 129, t. 11, 1851. No. 



