FREE INSTITUTE OF SCIENCE 



TERTIARY FAUNA OF FLORIDA "' ^ 



Tropical and temperate waters of the Old World. Parembola Romer is syn- 

 onymous. 



Section Tapes Megerle s. s. {vide supra). 



Section PoUtitapes Chiamenti, 1900. Type Venus aiirea Gmelin. 



Valves oblong, plump, not angular above, behind; the surface with fine 

 concentric sculpture and obscure radial striation ; lunule small, circumscribed : 

 escutcheon not defined ; pallial sinus short, ascending, free below, rounded in 

 front ; color delicate and variable. 



This is Tapes Sacco, not Megerle. The siphons are united for three- 

 quarters of their length in the British species (T. virgineiis), which is not 

 known to form a byssus. 



Section Ptillastra Sowerby, 1826. Type Venus puUastra Montagu. 



Shell oblong, tumid, blunt behind ; valves finely reticulately sculptured ; 

 the lunule and escutcheon are hardly differentiated, the latter nearly linear; 

 the inner margins are entire ; the pallial sinus deep, horizontal, ample, rounded 

 in front and confluent with the pallial line below ; the siphons in the type are 

 separated for about one-fourth of their length ; the two posterior right and 

 middle left cardinals are bifid ; the coloration is feeble. 



Section Myrsus H. and A. Adams, 1858. Type Tapes corrugatus 

 Deshayes. 



Valves as in PuUastra, but the concentric surface sculpture is broken and 

 corrugated and the shell, having a nestling habit, is very variable in outline ; 

 teeth as in PuUastra; the lunule obscure or not defined, the margin of the 

 escutcheon feebly carinate; the pallial sinus is small, slightly ascending, free 

 below and rounded in front ; the inner margins are smooth ; the coloration 

 dull and unattractive. 



This is Metis Adams, 1857, not 1856; Myrsopsis (pernarum Bonelli) 

 Sacco, 1900, from the Italian tertiaries, does not appreciably differ. 



Subgenus Ruditapes Chiamenti, 1900. Type Venus decussata Linne. 



Valves convex, oblong ; surface dull and feebly colored ; sculpture strong 

 distally, more or less reticulate, the concentric ridges more or less inosculating 

 anteriorly and feeble on the middle of the shell, the radial sculpture stronger; 

 internal margins smooth ; the pallial sinus horizontal, large, free below, 

 rounded in front ; the lunule circumscribed, the escutcheon feebly defined ; all 

 the inner cardinals more or less bifid ; the siphons are wholly free from each 



