TRANSACTIONS OF WAGNER 

 1316 



TERTIARY FAUNA OF FLORIDA 



Mercenaria fulgurans Tryon, Am. Journ. Conch., i., p. 297, pi. xxvi., figs. 1-3, 1865 (young 



shell). 

 Venus tetrica Conrad, Fos. Medial Tert., p. 7, pi. iv., fig. I, 1838; Bull. Nat. Inst., ii., p. 



187, 1842. 

 Mercenaria tetrica Conrad, Proc. Acad. Nat. Sci. Phila., xiv., p. 574, 1863; Meek, Checkl. 



Miocene Fos., p. 9, 1864. 

 Venus permagna Conrad, Fos. Medial Tert., p. 9, 1838 ; Proc. Acad. Nat. Sci. Phila., i., p. 



324, 1844; Tuomey and Holmes, Pleioc. Fos. S. Car., p. 86, pi. xxii., fig. 2, 1856. 

 Mercenaria permagna Conrad, Proc. Acad. Nat. Sci. Phila., xiv., p. 574, 1863 ; Meek, 



Checkl. Miocene Fos., p. 9, 1864. 

 Venus cafa.r Conrad, Proc. Acad. Nat. Sci. Phila., i., p. 324, 1844; Fos. Medial Tert., p. 



68, pi. xxxviii., fig. 4, 1845. 

 Mercenaria capax Conrad, Proc. Acad. Nat. Sci. Phila., xiv., p. 574, 1863 ; Meek, Checkl. 



Miocene Fos., p. 9, 1864. 

 Venus submortoni Orbigny, Prodr. Pak, iii., p. 208, 1852. 

 Mercenaria submortoni Conrad, Proc. Acad. Nat. Sci. Phila., xiv., p. 574, 1863 ; Meek, 



Checkl. Mioc. Fos., p. 9, 1864. 

 Mercenaria obtusa Conrad, Am. Journ. Conch., ii., p. 104, pi. viii., fig. 3, 1866; not Venus 



obtusa Sedgvv'ick and Murchison, 1844. 

 Mercenaria cuneata Conrad, Am. Journ. Conch., iv., p. 278, pi. xx., fig. i. 1868. 

 Mercenaria carolinensis Conrad, in Kerr. Geol. Rep. N. Car., App., p. 20. 1875. 



Miocene of Maryland and Virginia, the Carolinas and Florida ; Pliocene of 

 the Brunswick Canal, Georgia, and of Shell Creek, Florida; Pleistocene of 

 South Carolina, Florida, and the shores of the Gulf of Mexico ; living from 

 Chesapeake Bay southward to Cuba, westward to Texas and Yucatan in mod- 

 erate depths of water. 



Careful study of a large series of recent specimens leads to the formulation 

 of the following characters as distinctive of this species : 



The adult shell is shorter, rounder, larger, and much thicker than that of 

 V. mercenaria; it is usually wholly white internally ; the lunule is wider than 

 in V. mercenaria, the escutcheon better defined and wider, the disk wholly 

 covered with fine, close lamellation, which is not obsolete on the middle of the 

 valves nor colored red-brown or black ; the lower posterior angle of the pallial 

 sinus is generally more acute, the crenulation of the inner margin finer, and 

 the disposition of the cardinal teeth less fan-like than in V. mercenaria. 



The young shell is less convex than in the other species, as a rule, and is 

 almost invariably white, with a brown lunule and escutcheon, and fine, pale- 

 brown zigzag lines * or pale alternating with brown rays showing through the 



* In this state it forms the V. fulgurans of Tryon. 



