152 BULLETIN 90, UNITED STATES NATIONAL MUSEUM. 



equally descending; anterior end longer, evenly rounded into the 

 base, which is arcuate and rather prominent mesially; posterior end 

 bluntly rounded and attenuate; interior with the pallial markings 

 obscured; hinge with two strong laterals and two adjacent cardinal 

 teeth, of which the posterior is larger and grooved. Length 11, height 

 9, double diameter 2.75 mm. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida. E. J. 

 Post. U. S. Nat. Mus. No. 165220. 



A single right valve was received too late for figuring, but the 

 species is well marked. 



Section MACALIOFSIS Cossmann. 



Macaliopsis Cossmann, Cat. Illustr. bassin de Paris, p. 63, 1886. Type, 

 Tellina harrandei Deshayes. — Dall, Titans. Wagner Inst., vol. 3, pt. 5, 

 p. 1010, 1900. 



TELLINA (MACALIOPSIS) MERULA Dall. 

 Plate 24, fig. 7. 



Tellina (Macaliopsis) (?) merula Dall, Trans. Wagner Inst., vol. 3, pt. 5, 

 p. 1019, pi. 46, fig. 4, 1900. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida. U. S. 

 Nat. Mus. No. 157848. 

 The species recalls T. mera Say, but is of different form. 



Subgenus ARCOPAGIA Leach. 



Arcopagia Leach, in Brown, 111. Conch. Gt. Britain, p. ii, pi. 16, fig. 8, 

 1827 ; Tellina crassa Montague. — Dall, Trans. Wagner Inst., voL 3, pt. 

 5, p. 1011, 1000. 



Cydippe Leach, Moll. Gt. Brit, p. 314, 1852 ; same type. 



Section MERISCA Dall. 



Merisca Dall, Proc. U. S. Nat. Mus., vol. 23, No. 1210, p. 290. Type, Tellina 

 crystalUna Wood. — Dall, Trans. Wagner Inst., vol. 3, pt. 5, p. 1012, 

 1900. 



TELLINA (MERISCA) HALIDONA Dall. 



Plate 23, figs. 1, 3. 



Tellina (Merisca) halidona Dall, Trans. Wagner Inst., vol. 3, pt. 5, 

 p. 1021, pi. 38, figs. 3, 3a, 1900. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida, U. S. 

 Nat. Mus. No. 157856. 



Only a single left valve of this species is known. 



