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TERTIARY FAUNA OF FLORIDA ^ ^ 



Phacoides (Parvilucina) crenulatus Conrad. 



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PLATE 52, FIGURE 12. 



Lucina crenulata Conrad, in Morton, Synops. Org. Rem., App., p. 2, 1834; Journ. Acad. 



Nat. Sci. Phila., vii., p. 125, 1834; nude names. 

 Lucina crenulata Conrad, Fos. Medial Tert, p. 39, pi. xix. (2d ed.), fig. 8; pi. xx., fig. 2, 



May, 1840; Bull. Nat. Inst., No. ii., p. 181, 1842; Tuomey and Holmes, Pleioc. Fos. 



S. Car., p. 60, pi. xviii., figs. 14-15, 1857; Emmons, Geol. Rep. N. Car., p. 291, fig. 217, 



1858; Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 577, 1863; Gabb, Geol. St. 



Domingo, p. 251, 1873; Whitfield, Mio. Moll. N. J., p. 63, pi. x., figs. 7-15, 1895; not 



of Searles Wood, 1850. 

 Lucina lens H. C. Lea, Trans. Am. Phil. Soc., 2d Ser., ix., p. 240, pi. xxxiv., fig. 19, 1845 ; 



not of Deshayes, 1843. 

 Lucina Leana Orbigny, Prodr. Pal., Hi., p. 117, 1852; Conrad, Proc. Acad. Nat. Sci. 



Phila., xiv., p. 577, 1863. 



Miocene (mixed with Oligocene) of Jericho, New Jersey; Miocene of 

 Maryland at Plum Point, St. Mary's River, Calvert Cliffs, and Jones Wharf; 

 of Virginia at Petersburg, Yorktown, other localities on the York River, and 

 Suffolk (type locality) ; of North Carolina at Wilmington, and Magnolia and 

 the Natural Well in Duplin County; of Florida, in the upper bed at Alum 

 Bluff, Chattahoochee River. 



The original locality of this species is at Suffolk, Virginia, where it is 

 abundant. The Suffolk specimens have therefore been taken as a standard 

 with which the material from other localities and horizons might be compared, 

 and, as is natural, it has been found that some of the forms hitherto very gen- 

 erally regarded as or called by the name of crenulatus are sufficiently distinct to 

 be specifically separated from the Suffolk fossil. The latter is a moderately 

 convex, slightly inequilateral shell, rather solid, with inconspicuous, slightly 

 prosogyrate beaks, moderately excavated lanceolate lunule, and dorsal areas 

 indicated only by the absence of radial sculpture. The disk is sculptured by 

 more or less distinct, low, close-set, radial threads which do not cancellate the 

 concentric sculpture of numerous rather stout, low, flat-topped lamellae, sepa- 

 rated by slightly wider interspaces, and on the dorsal areas rather thinner and 

 more elevated. The hinge is well developed and the inner margins are finely 

 crenulated. The average adult dimensions are: Alt. ,6.0, Ion. 6.5, diam. 4.0 

 mm., but rare individuals attain a length of as much as 8.0 mm. 



The specimens from Alum Bluff, Florida, form a variety which may be 

 named pemphigus and which differs from the original type by its more convex 

 and rounded form, stronger hinge, more prominent and close-set concentric 



