128 MOLLUSCA OF THE GuLF OF MEXICO 98 



Distribution. — Hatteras to Haiti and West Florida, moder- 

 ate depths. Pliocene. Caloosahatchie River and Shell 

 Creek, West Fla. 



cerithioides Dall, Bull. M. C. Z., i8, p. 258, '89; Bull. 37, U. S. 

 N. M., p. 140, '89; Tr. W. I. S., 3, p. 276, pi. 16, f. 8, '92; 

 Dall and Simpson, Bull, U. S. Fish Com., i, p. 427, 1901. 

 (All as Bittium ccrithioidc). 



Distribution. — Cape Lookout, N. C to Samana Bay, Do- 

 minican Republic. vSingley lists with a question a shell from 

 Corpus Christi, Tex. Pliocene, Caloosahatchie River, Fla. 



Genus BlTTIUIVl (Leach) Gray 



varium Pfeiffer, Arch, fur Naturg., p. 256, No. 139, 1840, (as 

 Cerithium) ; Trj^on,Man., 9, p. 152, pi. 29, f. 86, '87; Dall, 

 Tr. W. I. S., 3, p. 274, '92; Dall and Simpson, Bull. U. S. 

 Fish Com., i, p. 426, 1901. 



gibberulum C. B. Adams, Pr. Bost. Soc. N. H,, p. 5, 1845; 

 Sowerby's Thes., p. 876, f. 210, 211, (as Cerithium). 



Distribution. — Chesapeake Bay to St. Thomas, W. I. Gulf 

 coast: Cedar Keys, Fla.; Chandeleurs, La.; Corpus Christi, 

 Galveston and Laguna Madre, Tex. Pleistocene, North 

 Beach. Fla. Pliocene, Caloosahatchie and Shell Creek, 

 Florida. 



Note. — Bittium nigrum Totten, synonym of B. alternation 

 Say, has been erroneously reported from Cedar Keys, Fla. 

 and Chandeleurs, La. These specimens were probably 

 variaim. True alternation, tide Dall, does not extend south- 

 ward of New York Harbor. 



boiplex Dall, Tr. W. I. S., 3, p. 275, pi. 21, f. 14, '92. 



Distribution. — Lower Miocene, Chipola marl, Fla., and of 



the Basom No. i well. Mobile, Ala. at 1500-1556 ft., Chipola 

 horizon, Aldrich's collection. A varietal form. 



