TRANSACTIONS OF WAGNER 

 764 

 ' ^ TERTIARY FAUNA OF FLORIDA 



Plicatula marginata Say. 

 Plicatula marginata Say, Journ. Acad. Nat. Sci. Phila., iv., pp. 136-7, pi. 9, fig. 4, 1824 ; 



Conrad, Fos. Med. Tert, p. 75, pi. 43, fig. 5, 1845 ; Tuomey and Holmes, Pleioc. 



Fos. S. Car., p. 24, pi. 7, figs. 11-14, 1855. 

 Plicatula rudis H. C. Lea, Trans. Am. Phil. Soc, N. S., i.x., p. 246, pi. 35, fig. 34, 1845. 



Miocene of Petersbuig, Virginia, Lea; of Coggins Point, Virginia, E. 

 Ruffin ; of York River, Virginia, Harris ; of Duplin County, North Carolina, 

 Murfreesborough and Wilmington, North Carolina, Haldeman and Stanton ; 

 of Darlington, South Carolina, Burns ; Pliocene of De Leon Springs (Wright), 

 and of thfe Caloosahatchie marls on the Caloosahatchie, Shell Creek, and 

 Alligator Creek, Dall and Willcox ; of the Waccainaw River, South Carolina, 

 Johnson ; and of Cape Fear, North Carolina, Dr. Yarrow. 



So far as the form of the shell is concerned, this species cannot be dis- 

 criminated from P. gibbosa, but none of the specimens show any trace of the 

 dark venous lines which are so characteristic of both recent and fossil speci- 

 mens of gibbosa. In a very large series of the recent shell a few specimens 

 will usually be found which have a diffused brownish blush instead of the 

 brown lines ; but these are so exceptional that I have felt the present species 

 might be separated with propriety. In both the differences of sculpture due 

 to situs pass through a parallel series of mutations. 



The genus Ostrenoiiiia Conrad, referred to in the synonymy, is in my 

 opinion based on a specimen of Plicatula which incidentally grew around the 

 stem of a Gorgonian or other round object, as there is no byssal scar. The 

 specimens were from the Eocene of North Carolina. 



There are a number of Cretaceous species of Plicatula, but I have been 

 unable to find any other Tertiary forms from America cited in the literature 

 besides those above mentioned. 



Family DIMYACIDtE. 



Genus DIMYA Rouault. 



Dimya grandis Dall. 

 Plate 35, Figure S. 

 Dimya grandis Dall, Proc. U. S. Nat. Mus., xix., No. ino, p. 328, 1896. 

 Oligocene of St. Domingo, at the Potrero, Rio Amina ; Bland. 

 The recent D. argcntea Dall has not been found fossil. The present 

 species may not improbably hereafter be found in the Chipola beds. 



