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T 45 



TERTIARY FAUNA OF FLORIDA 



the rest ; surface sculpture more pustular and less regular than in E. arcinella. 

 Length 50, height 48, diameter about 40 mm. exclusive of the spines. 



This species when compared is seen to be very distinct from the type of 

 the genus with which it was confused by Guppy and is really more like the 

 Pacific species, which has nearly as many ribs but differs by having a smaller 

 and less impressed lunule and long, cylindrical spines. 



All the species have occasional individuals which have the spines and even 

 the ribs nearly obsolete. Guppy 's Haitian specimen, and a valve collected in 



the Pliocene of Moen, Costa Rica, by Gabb, are of this character, but as it is 



i 



more an individual mutation than a true variety I shall not apply any distinctive 

 name to it. 



Echinochama arcinella Linn. 

 Chama arcinella Linne, Syst. Nat., ed. xii., p. 1139, 1767; Reeve, Conch. Icon., iv., pi. v., 



fig. 26 a, b, 1846; Orbigny, Moll. Cubana, ii., p. 362, pi. xxviii., figs. 28, 29, 1853 



(variety with long spines). 

 Cardium cristagalli Martyn, Univ. Conch., pi. cxxxii., fig. i, 1789 (variety with long 



spines). 



Arcinella spinosa Schumacher, Essai, p. 142, pi. xiii., fig. i, 1817. 



Cardium histrix Martyn, Univ. Conch., pi. cxxxii., fig. 2, 1789 (variety with short spines). 

 Chama arcinella Conrad, Am. Journ. Sci., 2d Ser., i., p. 404, 1846; Tuomey and Holmes, 



Pleioc. Fos. S. Car., p. 22, pi. vii., figs. 4, 5, 6, 1855; Emmons, Geol. Rep. N. Car., 



p. 287, fig. 209, 1858; Holmes, Pleist. Fos. S. Car., p. 23 (pi. v., fig. i, excl.), 1860; 



Meek, Checkl. Mioc. Fos. N. Am., p. 8, 1864; Gabb, Geol. St. Dom., p. 251, 1873; 



Heilprin, Trans. Wagner Inst., i., p. 103, 1887. 

 Arcinella arcinella Morch, Cat. Yoldi, ii., p. 37, 1853; Conrad, Proc. Acad. Nat. Sci. 



Phila., xiv., p. 576, 1864. 



Arcinella cornuta Conrad, Am. Journ. Conch., ii., p. 105, 1866. 

 Chama (Echinochama) arcinella Fischer, Man. de Conchyl., p. 1049, 1887. 

 Chama (Arcinella) spinosa H. and A. Adams, Gen. Rec. Moll., ii., p. 464, 1857. 



Pliocene marls of the Caloosahatchie, Shell Creek, and Alligator Creek, 

 south Florida, also at De Leon Springs (Wright) and Shoal River, Walton 

 County, Florida, Burns ; living from Cape Fear, North Carolina, to San Paulo, 

 Brazil, and through the Antilles from near low-water mark to twenty-six 

 fathoms. 



This well-known species was described from a recent specimen with rather 

 long spines by Linne. Its chief variations are in the length of the spines, their 

 number being occasionally increased by intercalation, and in coloration. Those 

 from Florida are usually white externally, frequently with a pink flush inter- 

 nally, while the Antillean specimens are usually more or less brown or ferru- 



