TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



Cytherea verrucosa has the siphons short, but mostly free from each other, 

 their orifices and the mantle margin fringed, and the foot geniculate. 

 This genus is divisible into two groups or subgenera as follows : 



Genus Cytherea Bolten. Type Venus puerpera L. Dental formula ^■°'°'°'°' 



Shell large and rotund, valves convex, vi^ith strong sculpture in which the 

 concentric element predominates, with well-marked lunule and escutcheon, the 

 latter unequally divided between the valves, larger in the left valve ; umbones 

 plump ; ligament set in a groove ; cardinals large, the middle left and the 

 posterior two right cardinals bifid, the left anterior lateral papilliform, obscure, 

 sometimes obsolete ; pallial line with a small, short, rounded sinus ; inner 

 margins of the valves crenulate. 



Subgenus Cytherea s. s. 



Shell large, reticulately sculptured ; the portion of the escutcheon in the 

 right valve (when not defective) forming a thin lamina which projects over the 

 sunken ligament and almost completely hides it; pallial sinus wide, short, and 

 rather rounded in front ; lateral tooth minute or obsolete. 



Section Clausina Brown.* Type V. verrucosa Linne. 



Shell large, strongly concentrically lamellose with obscure divaricating 

 radials towards the ends ; right portion of the escutcheon slightly overlapping 

 behind but not over the ligament ; pallial sinus small, narrow, angular. 



Section Ventricola Romer. Type V. ritgosa Gmelin. 



Shell large with strong, recurved, concentric lamellae regularly spaced, be- 

 tween which are smaller concentric threads ; pallial sinus small, angular ; lunule 

 deeply impressed. 



Subgenus APHRODINA Conrad. 



Aphrodina Conrad, Am. Journ. Conch., iv., p. 246, 1868 {Meretrix tippana Conrad) ; 

 Kerr, Geol. Rep. N. Car., App., p. 7, 1875; Meek, Pal. Upper Missouri, p. 179, 1876; 

 Tryon, Syst. Conch,, iii., p. 177, 1884. 



■ Shell concentrically striated, with a circumscribed lunule, but no defined 

 escutcheon ; inner margins smooth ; pallial sinus ample, free, ascending, rather 

 rounded in front ; hinge with three cardinals in each valve, the right posterior 



* The name Vemisarius of Dumeril is older, but was given to the animal alone, 

 under a non-Linnean system of nomenclature. 



