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969 



TERTIARY FAUNA OF FLORIDA 



ation in tropical waters, but cannot be subdivided naturally. It is this shell 

 which is usually referred to by Cooper and others when they cite D. nexuosa 

 Gld. from various Californian horizons. 



The only other unmentioned Pliocene species is D. moencnsis Gabb (Journ. 

 Acad. Nat. Sci. Phila., 2d Sen, viii., p. 371, pi. 47, fig. 72, 1881) from the 

 Pliocene of Costa Rica near Port Limon. It is a small shell and may prove 

 immature. 



D. californica Deshayes was founded on pale specimens of D. culter Han- 

 ley, and has not yet been reported in the fossil state. 



Donax Isevigata Deshayes. 



Donax licvigata Deshayes, P. Z. S., 1854, p. 352 ; Reeve, Conch. Icon., viii., pi. 5, fig. 31. 

 Donax obesus Gould, Proc. B. Soc. N. Hist., iv., p. 90, Nov., 1851 ; Boston Journ. Nat. 

 Hist., vi., p. 395, pi. 15, fig. 9, Oct., 1853; Philippi, Zeitschr. Mai., 1851, p. 75; not of 

 D'Orbigny, 1843. 



Donax californica of several Californian authors (not of Conrad or Deshayes) and of 

 . Carpenter, Maz. Cat., p. 47, 1857. 



Pleistocene of San Pedro Hill and of San Diego, California, Stearns and 

 Dall ; recent, from Santa Barbara southward. 



This is the common species of California, used for food, and the west coast 

 analogue in the fauna of the east coast D. variabilis. It varies, like all the 

 other species, in outline, but in general has very uniform characters. Re- 

 markably fine specimens of it are abundant in the Pleistocene of San Pedro 

 Hill. 



Donax variabilis Say. 

 Donax variabilis Say, Journ. Acad. Nat. Sci. Phila., ii., p. 305, 1822; Tryon, Am. Mar. 



Conch., p. 154, pi. 27, figs. 378-9, 1873 ; not of Tuomey and Holmes, 1857. 



Pleistocene of Florida in many localities ; recent from Cape Hatteras, 

 North Carolina, to St. Thomas, West Indies. 



This, the most abundant species of the eastern coast, has not turned up in 

 any beds older than the Pleistocene, and of those, so far, only in Florida. Asso- 

 ciated with the recent shells from South Carolina to Texas and usually con- 

 founded with variabilis is a form nearly intermediate between the latter and 

 the Texan D. Riruicri Phil., but this has not yet been found fossil. 



In California the southern D. culter Hanley (1845, -\- D. californica Desh. 

 non Conr., -)- D. Conradi Desh., 1854; + !). contusus Reeve) reaches to San 

 Diego, but this also is not yet known as a fossil. 



