FREE INSTITUTE OF SCIENCE 



067 



TERTIARY FAUNA OF FLORIDA 



Doubtless a more thorough search of the Oligocene beds would reveal 

 additional species of this family. 



Donax Emmonsi Dall. 

 PLATE 28, FIGURE 16. 

 Donax Emmonsi Dall, Nautilus, v., No. n, p. 126, March, 1892; Emmons, Geol. N. Car., 



p. 298, fig. 227, 1858; Dall, Trans. Wagner Inst., iii., p. 923, pi. 28, fig. 16, 1898. 



Miocene of North Carolina, in Duplin County, at the Natural Well and 

 Magnolia, Burns; Pliocene of the Cape Fear River, at Mrs. Guion's marl bed, 

 C. W. Johnson. 



This species is more triangular than any of the recent forms of the coast, 

 faintly radially striate, ventrally somewhat flexuous, and with a sharply serrate 

 margin. The teeth are normal and strong, especially the sockets for the 

 laterals. Lon. 10, alt. 7, diam. 4 mm. 



Donax fossor Say. 

 Donax fossor Say, Journ. Acad. Nat. Sci. Phila., ii., p. 306, 1822 ; Tryon, Am. Mar. Conch., 



p. 153, pi. 27, figs. 376, 377, 1873. 

 Donax variabilis Tuomey and Holmes, Pleioc. Fos. S. Car., p. 95, pi. 23, fig. 6, 1857; not 



of Say. 



Donax angustatus Sowerby, Thes. Conch., iii., p. 309, pi. 281, fig. 44, 1866. 

 Donax protractus Conrad, Journ. Acad. Nat. Sci. Phila., 2d Ser., i, p. 208, pi. 39, fig.' 8, 



1849 (senile stage). 

 Donax parvula Phil., Zeitschr. Mai., p. 146, 1845 (young shell). 



Miocene of Duplin County, North Carolina, at Magnolia, Burns ; Pliocene 

 of the Waccamaw beds, South Carolina ; of the Cape Fear River, North Caro- 

 lina; and of the Caloosahatchie beds of Florida; Pleistocene of Simmons 

 Bluff, South Carolina, Burns ; recent, from New Jersey to the Florida Keys. 



Although Donax variabilis Say has several times been reported from the 

 Miocene and Pliocene, the specimens when critically studied have so far turned 

 out to be D. fossor. 



Other Miocene forms are D. idonea Conrad (Proc. Acad. Nat. Sci. Phila., 

 xxiv., p. 216, pi. 7, fig. 2, 1872), a large form supposed to have been washed 

 out of submarine Miocene beds on the coast of North Carolina; Donax tumida 

 Philippi (Zeitschr. Mai., p. 147, 1848), a recent Texan species, identified by 

 Harris from the fossils of the Galveston artesian well, supposed to be Upper 

 Miocene; and D. (Macharodonax) galvestonensis Harris, from the same 

 source, described by Harris (Bull. Pal., ii., p. 92, 1895) as a variety of the 

 Pacific coast recent D. (Machcerodonax) carinata Hanley. 



