TRANSACTIONS OF WAGNER 

 1OI2 



TERTIARY FAUNA OF FLORIDA 



Section Cydotellina Cossmann, 1886. Type Telllna lunulata Deshayes. 



Shell with the shape and sculpture of Arcopagia, the anterior left lateral 

 sometimes present (as in the type), the sinus more or less confluent below, 

 anterior and posterior radii more or less developed. Lower Parisian Eocene 

 to recent in the warmer seas. 



This group may perhaps be extended to include most of the large rotund 

 species which have erroneously been referred to Arcopagia, such as T. fausta, 

 remies, and discus, which have a partially confluent sinus, often linked to 

 the anterior adductor scar by a linear scar, but in other respects agreeing 

 with Arcopagia. Arcopagiopsis Cossmann has the fully developed hinge of 

 Tellina and sharp sculpture, allying it more closely to the section Macaliopsis, 

 from which it can hardly be separated. 



Section Merisca Dall, 1900. 



This group comprises more or less trigonal, usually rather convex shells, 

 of small or moderate size, with lamellose concentric sculpture, and often fine 

 radial striae in the interspaces ; there is a narrow but sharp posterior flexure ; 

 the laterals of the right valve are strongly developed, but the left valve is 

 without lateral teeth, its margin fitting above the laterals of the opposite 

 valve; the pallial sinus is ample, frequently wholly confluent below, and 

 always largely confluent, the dorsal portion often represented only by a line 

 connecting the adductors. 



These shells are related to Macaliopsis, from which they differ by the 

 absence of lateral teeth in the left valve ; to Moerella, from which their sculp- 

 ture and posterior fold separate them ; and to Pseudarcopagia, which is not 

 rostrate and has no fold, while its radial sculpture is more conspicuous. The 

 recent species are usually pale, without color markings, or white, and Inhabit 

 the warmer seas. 



Section Phyllodina Dall, 1900. Type Tellina squamifcra Deshayes. 



Shell elongate, inequivalve, with a sharp concentric sculpture rising into 

 leaflets along the dorsal border; fold conspicuous; hinge with well-marked 

 right laterals and a feeble anterior left lateral, distant from the cardinals; 

 sinus short, ascending, blunt behind and free below from the pallial line as 

 in Arcopagia; interior without thickened radii. Oligocene to recent. 



This elegant shell, described from a single specimen of unknown habitat, 

 has erroneously been referred to Chinese seas, but is now known to be Ameri- 

 can. Its characters recall Phylloda and it can hardly find a place in other 

 sections, especially as it has several fossil representatives. 



