290 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiii. 



Section ArcojxigelJa INIeek, 1871. Tj'pe, ArcojMgellit mactroidm 

 Meek, (Cretaceous. ) 

 Shell with the form and sculpture of Moerella, the sinus of Arco- 

 jjagia^ and the hinge of Tellina. 



Subgenus Linearia Conrad, 1S()0. Type, Linearla metastriata Con- 

 rad. (Cretaceous.) 



h. Hinge with two lateral lainince, in the rigid valve^ the laminm of the 

 left valve more or less ohsolete^ or absent. 



Subg-enus Elliptotellina Cossmann, 1866. Type, Tellina telUnella 

 Lamarck. (Eocene.) 



Subgenus Pseudarcopagia Bertin, 1878. Type, Tellina decussata 

 Lamarck. 



Subgenus Arcopagia (Leach), 1827. T^'pe, Tellina crassa Pennant. 

 Cydippe (Leach), 1852, not Eschscholtz, 1829; not Arcopagia 

 Orbigny, 1853, 



Section Cyclotellina Cossmann, 1886. Type, Tellina lunulata 

 Deshayes. (Eocene.) 



Section Phyllodina Dall, 1900. Type, Tellina squamifera De- 

 shayes. 

 This has the form of Phylloda, and the sinus of Arcopagia. 



Section Merisca Dall, 1900. T3q3e, Tellina crystallina Wood. 



This group ( omprises more or less trigonal, usually rather convex 

 shells of small or moderate size, with lamellose concentric sculpture 

 and often fine radial lines 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 l)y a line connecting the 

 adductors. 



These shells are related to Macaliopsis., from which they difi'er in 

 the absence of lateral teeth in the left valve; to Moerella., from which 

 the sculpture and posterior fold separate them* and to Pseadarcopagia., 

 which is not rostrate nor folded, Avhile its radial sculpture is more 

 conspicuous. The recent species are usually pale, without color mark- 

 ings, or white, and inhabit the warmer seas. 



Section Eurytellina Fischer, 1887, Type, Tellina jyunicea, Born, 

 Peponcmderma^\.o\Q\x^ 1853, not Poli, 1795, 



Section Scrobiculina Dall, 1900, Type, Scrohicxdaria viridotincta 

 Carpenter, 



I 



