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I 367 



TERTIARY FAUNA OF FLORIDA ' 



cursor of P. sombrerensis Dall, a recent species from Antillean waters, which 

 is, however, larger, with more regular concentric sculpture, more delicate hinge, 

 and nearly obsolete lunule. An obscure radial impression, which was at first 

 taken to be pathological, extends on the fossil towards the anterior base. The 

 recent forms show faint traces of a similar sulcation. In them the anterior 

 dorsal area is not visibly delimited and the crenulation of the margins is more 

 feeble. 



Phacoides (Here) sp. indet. 



Oligocene of the Oak Grove sands, Santa Rosa County, Florida ; Burns. 



A single immature valve of what appears to be a species of Phacoides dif- 

 ferent from any of which adults have been described was found with the other 

 Oak Grove fossils. The shell is rather longer than high, with the nepionic 

 portion of the beak closely concentrically ribbed but the rest nearly smooth; 

 the anterior dorsal area is small, limited by a rather obscure, shallow, but narrow 

 sulcus ; the posterior area is set off by a broad, well-marked sulcus ; the lunule 

 is deep and wide, forming an excavation which intrudes across the hinge-line 

 between the anterior lateral and the cardinals. All the teeth are well developed. 

 Alt. 4.0, Ion. 4.5, diam. (double) 2.0 mm. 



The sculpture alters so with growth that I think it best not to name this 

 species until more material comes to hand. 



Phacoides (Here) Bichthofeni Gabb. 



Lucina (Here) Richthofeni Gabb, Pal. Cal., ii., p. 29, pi. viii., figs. 49 a-b, 1866. 

 Lucina excavata Carpenter, Mazatlan Cat., p. 98, 1857; not of Orbigny, 1851. 

 Phacoides (Here) Richthofeni Dall, Synopsis Lucinacea, Proc. U. S. Nat. Mus., xxiii., 



pp. 810, 827, pi. xl., figs. 7, 9, 1901. 



Pliocene of San Quentin Bay, Lower California, Orcutt ; living from Cata- 

 lina Island, California, south to the Gulf of California. 



This species is the type of the subgenus and has a very variable but occa- 

 sionally very capacious excavated lunule, which, contrary to the rule in P. 

 Glenni, increases in size with age. 



Phacoides (Here) densatus Conrad. 

 Lucina densata Conrad, Am. Journ. Conch., Hi., p. 13, 1867. 

 Lucina pennsylvanica Tuomey and Holmes, Pleioc. Fos. S. Car., p. 56, pi. xviii., fig. 3 



1856; not of Linnaeus, Syst. Nat., ed. x., p. 688, 1758. 



Oligocene of the Oak Grove sands, Santa Rosa County, Florida ; Miocene 



