TRANSACTIONS OF WAGNER 

 1276 



TERTIARY FAUNA OF FLORIDA 



Cytherea "Willcoxi n. sp. 

 Plate 53, Figure 3. 



Pliocene marl of the Caloosahatchie River, near the site of old Fort Thomp- 

 son ; Willcox and Dall. 



Shell large, capacious, with well-rounded, somewhat anteriorly twisted 

 beaks ; a cordate lunule unequally divided and larger in the right valve ; 

 escutcheon long, bordered by a wide, shallow sulcus more emphatic in the left 

 valve; sculpture of very numerous concentric lamellae widened and flattened at 

 the top so that they nearly (and sometimes quite) join over the interspaces, espe- 

 cially towards the base ; these lamellae, though sharper distally, do not rise into 

 wide, thin laminas, as in the well-developed individuals of C. Listeri, but re- 

 main of nearly the same height over the whole shell ; near the beaks fine radial 

 striation is notable in the interspaces, faintly crenulating the concentric lamellae 

 but becoming almost wholly obsolete as the shell approaches maturity ; hinge 

 solid, the two posterior cardinals in each valve deeply bifid; the anterior lateral 

 reduced to a low pustule; inner margins minutely crenulate; adductor scars 

 very large; pallial sinus ample, linguiform, rising above a line joining the 

 bases of the scars. Length 102, height 87, diameter 60 mm. 



Shell somewhat resembling the recent C. Listeri Gray of the Florida Keys, 

 but differing from it by larger size, much closer and more uniform concentric 

 lamellation, proportionally larger lunule and escutcheon, heavier hinge, pro- 

 portionately larger adductor scars, and more ascending pallial sinus. 



I take great pleasure in naming this splendid shell after Mr. Joseph Will- 

 cox, to whom we are indebted for so much in connection with the explorations 

 of the Pliocene and Oligocene of Florida, and for the discovery of this and 

 many other of their finest fossil remains. 



Cytherea (Ventricola) ucuttana n. sp. 



Plate 57, Figure 14. 



Red Bluff horizon of the lower Oligocene of Mississippi on Ucutta Creek, 

 Clarke County, Carson's Creek, and at Red Bluflf, Wayne County; Johnson, 

 Burns, and others. 



Shell small, moderately convex, rotund, with low, inconspicuous, proso- 

 gyrate beaks ; lunule small, slightly impressed, bounded by an impressed line ; 

 escutcheon very narrow, defined by a radial ridge sharper in the left valve; 

 surface sculptured with numerous low, even, gently rounded, wavelike con- 

 centric ridges and by fine, close, regular, low concentric threads which cover 

 the whole surface ; hinge solid, normal, well developed, the anterior lateral 



