TRANSACTIONS OF WAGNER 

 6l2 



TERTIARY FAUNA OF FLORIDA 



Bellefield, Yorktown, and other points on the York River and on the Eastern 

 Shore of Virginia, and Davis's Mill, Choptank River, Maryland. 



Variety plagia Dall, Edgecombe County, North Carolina. 



Variety Tiioincj'i Dall, Petersburg, City Point on James River, and near 

 Suffolk, Nansemond River, Virginia. 



Shell asymmetrically developed, inequilateral, the impressed lines more 

 or less arcuate and obsolete on the produced anterior side. 



This species is the oldest of those which reach the Upper Miocene. The 

 Chipola specimens are slightly smaller than the average Miocene shell, but 

 this may be an accident of collecting; otherwise they agree very well with 

 Miocene specimens. 



The normal adult is subcircular, with radiating impressed lines, the inter- 

 spaces being gently rounded and rather wide. The grooves are closer at the 

 ends of the shell and the interspaces less rounded. In the young the shell 

 seems to have close-set rounded ribs ; in senile specimens the radial grooves 

 are obsolete towards the base. The principal mutations of the normal adult 

 are greater or less prominence of the rounded interspaces, greater persistence 

 distally of the grooves, and smaller or larger, sparser or more crowded, hinge- 

 teeth and areal grooving. 



In the variety Tuomeyi the alternate interspaces are not rounded but flat, 

 forming channelled spaces, subequal to and between the ribs, which are often 

 more or less flattened on top and obsolete distally. 



In the variety plagia the shell is obliquely produced with the grooves 

 obsolete laterally. 



The Oak Grove series contains many specimens in which intercalary 

 incised lines appear on the rounded interspaces distally and the lines are 

 much crowded at the ends of the shell. An occasional specimen turns up 

 where the whole shell is nearly smooth, the incised lines being obsolete. In 

 this state it is much like G. Icevis T. and II. externally, but larger and more 

 rounded dorsally. 



Glycymeris pectinata Gmelin. 

 Area pectinata Gmel., Syst. Nat., vi., p. 3313, 1792. 

 Pectunculus aratus Conr., Am. Journ. Sci., xli., p. 346, 1841 ; Med. Tert., p. 62, pi. 34, 



fig. 2, 1845 ; Tuomey and Holmes, Pleioc. Fos. S. Car., p. 50, pi. 17, fig. 6, 1857. 

 Pectunculus pectinifonnis Orb. , Moll. Cuba, ii., p. 313, 1853; IK it of Lamarck. 

 I't-ctunculus ihini,^li>n t -nsis Holmes, P.-PI. Fos. S. Car., p. 16, pi. 3, fig. 5. 1860. 

 Pectunculns pectinatus Dall, Hull. Mus. Comp. Xool., xii., No. 6, p. 239, 1886. 



