TRANSACTIONS OF WAGNER 

 728 



TERTIARY FAUNA OF FLORIDA 



until intermediate specimens are obtained I should not feel justified in sup- 

 pressing the species. 



Pecten (Placopecten ?) marylandicus Wagner. 

 Pectcn marylandicus Wagner, Journ. Acad Nat. Sci. Phila. , viii., p. 51, pi. 2, fig. i, 1838. 

 Pcctcn tenuis H. C. Lea, Trans. Am. I'hil. Soc, 2d Ser., ix., p. 246, pi. 35, fig. 33, 1845. 



Miocene of the Patuxent River, at Jones's Wharf, Maryland, Wagner ; of 

 Petersburg, Virginia, Lea; and the Meherrin River, North Carolina. 



I have examined the types of P. viarylandiciis m the Academy's collec- 

 tion, and the type of Lea's species is in the collection of the National Museum. 



It is difficult to say to which section the species should be referred, as in 

 the typical P. marylandicus the radiating threads often are gathered into fasci- 

 cles (fifteen to seventeen) which crenulate the valve margin, while in P. tenuis 

 the threads are not fasciculated and the margin is entire. In the former the 

 interior is fluted, in harmony with the external sculpture, while in the type of 

 tenuis the fluting is quite obsolete, though there are faint radial striations near 

 the margin. In marylandicus the radial sculpture averages coarser than in 

 tenuis. Yet these differences march closely with those observed in a large 

 series of P. hericeus Gould from the northwest coast, and the other characters 

 are so similar that I feel indisposed to assign specific rank to the differences. 



In the largest and finest specimens of P. marylandiciis there are fluctuated 

 scales concentrically arranged on each side of a mesial thread, in the inter- 

 spaces between the principal ribs. The shell attains an altitude of ninety and a 

 width of ninety-five millimetres, and the byssal notch is deep and conspicuous. 

 The species forms a transitional link between Placopecten and Chlamys s. s. 



Pecten (Nodipecten) nodosus Linne. 

 Ostrea nodosa L., Syst. Nat., Ed. x., p. 697, No. 164, 1758 ; Ed. xii., p. 1 145, 1767. 

 Pecten coralliniis Chemn., Conch. Cab., vii., p. 306, pi. 64, figs. 609-11, 1784. 

 Pecten nodosits Lam., An. s. Vert., vi., p. 170, 1819 ; d'Orb., Moll. Cuba, ii., p. 353, 



1845. 

 Pecten pcrnodostts Heilprin, Trans. Wagner Inst., i., p. 131, pi. \i>h, figs. 69, 69 a, 1887. 

 Pecten nodosus Heilprin, op. cit.. p. 100, 1887. 

 Pccte7i fragosus Conr., Journ. Acad. Nat. Sci. Phila., 2d Ser., i, p. 214, pi. 39, fig. 11, 



1849. 

 Pcctcn magnificus Gabb, Geol. St. Dom., p. 256, 1873 ; "ot of Sowerby, P. Z. S., 1835, 



p. 109. 

 Lyropcctcn nodosus Verrill, Trans. Conn. Acad., x., p. 91, 1897. 



Pliocene of the Caloosahatchie marls, Florida, Willcox ; Pleistocene of 



