FREE INSTITUTE OF SCIENCE 



TERTIARY FAUNA OK 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. fiassa is the normal adult; 

 (i. Icnti/iini/is, the senile adult; G. Iricaiaria is a half-grown, well developed 

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

 the ends of the shell ; G. tnuisi'crsa T. and H. (non Deshayes) is founded on 

 the internal cast of a rather wide young shell ; G. tiiiniiliis 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. qitinqiicntgata. 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 aincriaina and the quinquerugata without 

 rug;e 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 subovata Say. 



/',;/i/ihi//i/s sul'c^'d/ns Say, |oiirn. Arad. Nat. Sci., 1st Ser., iv., p. 140, pi. IO, fig. 4, 

 1824; Conrad, l-'os. Ten. I'onn., p. 17, pi. 2, fig. 3, 1832; Med. Tert., p. 62, pi. 34, 

 ML;, i, 1845 ; Kninions, C.col. Rep. N. Car., p. 286, tig. 207, 1858. 



G. eubovata var. Tuomeyi Dall. 

 r?i'tu>i,-ulffs sitlwatus Tuoim'y and Holmes, I'leioc. Fos. S. Car., p. 47, pi. 17, fig. I, 1857. 



G. subovata var. plagia Dall. 



if 

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



Rfver and Alum 151 uff, 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, 



4 



