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955 



TERTIARY FAUNA OF FLORIDA 



Ensatella americana Verrill, Inv. An. Vineyard Sound, p. 674, pi. 32, fig. 245, 1873 ; Am. 



Journ. Sci., iii., pp. 212, 284, 1872. 

 Ensis americana Dall, Bull. 37, U. S. Nat. Mus., p. 72, pi. 53, fig. 4, pi- 55. figs. 4, 5. 1889. 



Oligocene of the Oak Grove sands, Santa Rosa County, Florida. Miocene 

 of Maryland (Conrad); of Virginia at Petersburg; of North Carolina at 

 the Duplin County Natural Well ; of Darlington, South Carolina ; of Florida 

 in the upper bed at Alum Bluff; Pliocene of South Carolina; Pleistocene of 

 Heislerville, New Jersey ; Cornfield Harbor, Maryland ; Nantucket at Sankoty 

 Head and Point Shirley, Massachusetts, and Portland, Maine; recent from 

 Labrador to Indian Key, Florida. 



I began the examination of the fossil material supposing that the Miocene 

 form might be distinct from the recent shell, but after a series of careful com- 

 parisons I am unable to find any constant character by which they can be 

 discriminated. From . cnsifonnis the present species is distinguished by its 

 larger size and more squarely truncated posterior end. 



Ensis minor Dall. 



Pleistocene of Simmons Bluff, South Carolina, Burns; recent from Cape 

 May to Florida and Texas. 



This form is the " small variety" of " Solen ensis" described by Conrad 

 as long ago as 1831, and referred to by some authors as var. minor. It is 

 constantly smaller and more slender than E. directus, and has a tendency to 

 be wider at the posterior than at the anterior end. It is proportionately longer 

 than E. ensiformis, and is wider instead of attenuated and rounded behind. 

 It bears to the large E. directus the same relation that the true E. ensis of 

 Europe bears to the north European E. magnus Schum. 



Ensis ensiformis Conrad. 

 Solen ensiformis Conrad, Proc. Acad. Nat. Sci. Phila., i., p. 326, 1843 ; Fos. Medial 



Tert., p. 76, pi. 43, fig. 8, 1845. 



Miocene of Maryland at St. Mary's River (type locality), Choptank River, 

 and Cove Point ; of Virginia on the York and Nansemond Rivers ; the Natu- 

 ral Well and Magnolia, Duplin County, North Carolina; of Florida in the 

 rock excavated from the city reservoir at Jacksonville. Distinguished by its 

 straight, rather short, and posteriorly tapered and rounded form. 



Genus SILIQTJA Megerle. 



Siliqua Megerle, Mag. d. ges. Naturf. Fr., 1811, p. 44. Type Solen radiatus Linne; 

 Philippi, Handb. Conch., p. 331, 1853; H. and A. Adams, Gen. Rec. Moll., ii., p. 

 345, 1856; Fischer, Man. de Conchy!., p. nog, 1887. 



