FREE INSTITUTE OF SCIENCE 



74S 



TERTIARY FAUNA OF FLORIDA 



over the line, and separated from the present species more by its outline than 

 by any other important character, is the shell I have called Amu si urn ocalainnu, 

 all of which, with the aid of A. Lyoni Gabb, form a complete connecting series 

 between the most typical Aiinisinni and undoubted Clilatuys. 



Pecten (Plagioctenium) gibbus Linnr. 



(htri'a gibba L. , Syst. Nat., Ed. x., No. 172, p. 698, 1758; Ed. xii., No. 203, p. 1147, 



1 767. Jamaica. 



Not Os/n-a xihba Born, Test. Vindo., p. 107, 1780; nor 

 l\-ctfii riibiiitndiis gibbosus Ch., Conch. Cab., vii., p. 321, pi. 65, figs. 619-20, 1784; 



nor of Dilhvyn, Cat. Rec. Sh., i., p. 267, 1817 (in part). 

 Osln-ii hit.-a C.melin, Syst. Nat., vi., p. 3320 ; + O plana Ciiiielin, /. c. ; -|- O. flabellum 



Gmel., op. cit., p. 3321. 



l\'ftcn gibbits Sowerby, Thes. Conch., i., fig. 17 (only), 1843. 

 I't-i-tcn gibbus Reeve, Conch. Icon., pi. 9, figs. 37 />, 37 c, not fig. 37 a, 1852. 

 /'i /<;; Soi',-rl>ii (luilding, i<S26, not of Reeve, 1852. 

 l\'tten lUslocaliis Say, Journ. Acad. Nat. Sci. Phila., ii., p. 260, 1822 ; Am. Conch., Ivi., 



fig. 2, 2rt, 1834. 



/'i-//->t pin-piiratiis Conrad, Am. Mar. Conch., p. 10, pi. ii., fig. I, 1831 ; DeKay, Zool. 



N. Y., v., p. 174, 1843 ; not of Lamarck. 



Pcctcn t/is/in-a/us Holmes, Post-Pi. Fos. S. Car., p. 13, pi. ii., fig. 13, 1858. 

 l\-ct,-n citntliiris Ciiippy, I 'aria Fauna, p. 155, 1877 ; not of Sowerby. 

 I'l-i-tt-n gibbits Orb., Moll. Cuba, ii., p. 352, 1845 ; Krebs, W. I. Mar. Sh., p. 134, 1864; 



Arango, Fauna Mai. Cubana, ii., p. 270, 1878. 



l\;t,-n irmiUatis var. dislocatus Uall, Bull. U. S. Nat. Mus., No. 37, p. 34, No. 24, 1889. 

 Pcctfii nucleus Hcilprin, Trans. Wagner Inst., i., p. 102, 1886. 



Fossil in the later Miocene of the Nansemond River, Suffolk, Virginia, 

 Burns ; in the Pliocene of Florida, in the Caloosahatchie marls on the Caloosa- 

 hatchie, Shell Creek, Myakka River, and Alligator Creek, Willcox and Dall ; 

 in the Pleistocene of North Creek, Osprey, Florida, Dall, and of the Caro- 

 linas; also in the raised coral reefs of the Antilles. The Miocene specimens 

 are of the typical variety gibbiis ; the Caloosahatchie marls contain var. giblws 

 and var. ainplicostatus in about equal numbers ; the Pleistocene of North 

 Creek has var. gibbus and var. Iwrcalis, an indication of the more southerly 

 extension of the latter during the low temperatures of that epoch. 



This species is at present widely distributed, and is found living from 

 Cape Hattcras south to the Greater Antilles and Brazil, and on the continental 

 shore to Vera Cruz and the Bay of Campeachy; also on the northwest coast 

 of Africa, according to various authors. 



