FREE INSTITUTE OF SCIENCE 



TERTIARY FAUNA OF FLORIDA 



When these two sets of mutations are surperimposed it naturally happens 

 that the extreme instances are quite unlike ; without connecting links one 

 would, as Conrad and others have done, suppose them to represent distinct 

 species. A very careful and conscientious scrutiny of a large number of 

 specimens has resulted in the above synonymy. G. passa is the normal adult; 

 G. leiitiforniis, the senile adult; G. triccnaria is a half-grown, well developed 

 form ; G. carolincnsis Holmes is a variety with feeble ribbing, obsolescent at 

 the ends of the shell ; G. transversa T. and H. (non Deshayes) is founded on 

 the internal cast of a rather wide young shell ; G. iiirmdus Conr. is founded 

 on a rather inflated half-grown specimen. The only form which may possi- 

 bly be varietal, but which I am inclined to refer to some pathologic cause, is 

 G. quinqtieriigata. This is almost entirely confined to Duplin County, North 

 Carolina. Well-marked specimens have on each dorsal slope, from the beaks 

 laterally, three to six little irregular ripples, which are much more conspicu- 

 ous in the young. These might indicate the presence of some parasite in the 

 individual. They are never uniform or regular; some specimens have them 

 only on one side, in others they are obsolete, and, finally, others do not have 

 them ; and between the normal ainericana and the qiunqiceriigata without 

 rugse there is absolutely no distinction to be made. The recent shell is iden- 

 tical with Miocene specimens and reaches fully as large a size. 



The preceding species have more or less distinct radial striation, whether 

 there are ribs or not ; in those that follow there is no radial striation but more 

 or less distinct, fine, concentric sculpture and strong radial ribbing. 



Glycymeris sutaovata Say. 

 Pectunciilus subovattts Say, Journ. Acad. Nat. Sci., ist Ser., iv., p. 140, pi. 10, fig. 4, 

 1S24 ; Conrad, Fos. Tert. Form., p. 17, pi. 2, fig. 3, 1832; Med. Tert., p. 62, pi. 34, 

 fig. I, 1845 ; Emmons, Geol. Rep. N. Car., p. 286, fig. 207, 1858. 



Gr. subovata var. Tuomeyi Dall. 

 Pectunciilus subovatus Tuomey and Holmes, Pleioc. Fos. S. Car., p. 47, pi. 17, fig. i, 1857. 



G. subovata var. plagia Dall. 

 Oligocene: Vicksburgian of Martin Station, Florida ; Chipolan of Chipola 

 River and Alum Bluff, Calhoun County, and Oak Grove, Santa Rosa 

 County, Florida; Miocene of Walton County, Florida; of Dargan Point and 

 Darlington, South Carolina; of Duplin County, Edgecombe County, Green 

 County, and Wilmington, North Carolina.; of Grove Wharf, James River, 



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