FAUNA OF ORTHAULAX PUGNAX ZONE. 125 



SPONDYLUS CHIPOLANUS Dall. 



Plate 19, fig. 1. 



Spondylus (bostnjchites var. ?) cJiipolawus Dall, Trans. Wagner Inst., 

 pt. 4, p. 758, 1898. 



Oligocene of the Tampa silex beds at Ballast Point, Tampa Bay, 

 of the lower beds at Alum Bluff, Chattahoochee River ; of the Chi- 

 pola marls of Calhoun County, near the county bridge over the Chi- 

 pola Eiver; and of the sands at Oak Grove, Santa Eosa County, 

 Florida. U. S. Nat. Mus. No. 114817. 



This species at first suspected from poor material to be a variety 

 of S. hostrj/chites, has no radial striation on the minor ribs, but 

 rather a concentric sculpture, also a greater number of spinose ribs, 

 and more oval and inflated form. 



Genus PLICATULA Lamarck. 



PUcatula Lamarck, Syst. An. s. Vert., p. 132, 1801. Type, PUcatula gibhosa 



Lamarck An. s. Vert., P. ramosa Lamarck 1819. — Dall, Trans. Wagner 



Inst., vol. 3, pt. 4, p. 761, 1898. 

 Harpax Parkinson, Org. Rem., vol. 3, pi. 12, 1811. — Brooks, Intr. Conch., 



p. 83, 1815. Type, H. parTcinsonii Bronn. 

 Ostrcnoinia Conrad, Proc. Acad. Nat. Sci. Phila., for 1872, p. 216. Type, 



O. caroUnensis Conrad. 



PLICATULA DENSATA Conrad. 



PUcatula densaia Conrad, Proc. Acad. Nat. Sci. Phila.. vol. 1, p. 311, 1843. 



Medial Tert., p. 75, pi. 43, fig. 6. 1845; Proc. Acad. Nat. Sci. Phila., 



vol. 14, p. 582, 1863.— Dall, Trans. Wagner Inst., vol. 3, pt. 4, p. 763, 



1898. 

 Spondylus inornatus Whitfield, Miocene Pal. N. J., p. 34, pi. 5, figs. 1, 2, 



1895. 



Oligocene of the Peninsular limestone of Archer, Florida, and 

 the Nummulitic horizon at Ocala, Florida, Dall and Willcox; of 

 the Tampa silex beds at Ballast Point; the Chipola marls of Cal- 

 houn County ; of the lower bed at Alum Bluff on the Chattahoochee 

 River, and of the Oak Grove sands, Santa Rosa County, Florida; 

 also of the Bowden beds of Jamaica, West Indies, and the Guallava 

 beds of Costa Rica. Also in the lower Miocene marls of Cumber- 

 land County, New Jersey, at Shiloh and Jericho. U. S. N. Mus. No. 

 165183. 



This species is distinguished from the later P. marginata Say, 

 by its usually rounder form and more numerous and less prominent 

 plications. Occasional specimens when attached to a flat surface 

 by a considerable area of the attached valve, do not develop plica- 

 tions, and one such served as the type of Whitfield's Spondijlus 

 inornatus. 



