33 ^ Costa Rica Miocene — Olsson 159 



SUB-ORDER SCUTIBRANCHIATA - 

 A . S UPER-FAMIL Y RHIPIDOGL OSS A 

 Genus MERlTlNA Lamarck 

 Section SiVSARAGDlA Issel 



Nerltina Viridemaris Maury Plates 15, figure 22 



Nej'-itina viridis Gabb, 1873, Trans. Amer. Phil. Soc, vol, 15, p. 242, 



Not A^. viridis Linnaeus. 

 Neritina {^Smaragdia) virideniaris Maury, i9i7,Bull. Amer. Pal., vol. 



5, p. 316, pi. 24, fig. II. 



The Costa Rican specimens are a little smaller than typical 

 viridemaris from the Miocene of Santo Domingo; but are identi- 

 cal in other respects. They still retain their original coloration of 

 a pale sea-green marked with straight and zigzag black lines. It 

 is the Miocene precursor of the common, recent West Indian and 

 Caribbean A^. viridis Linne. 



Gatun Stage: Coll. 5, Red Cliff Creek. 

 Middle Creek. 



Genus CREPfDULA Lamarck 



Crepldula plana Say 



Crepidula plana Say, 1822, Journ. Acad. Nat. Sci. Phila. , vol. 2, p, 

 226. 



Crepidula plana Dall, 1892, Trans. Wagner Free Inst. Sci., vol. 3, pt. 

 2, p. 358. 



Crepidula plana Brown and Pilsbry, 191 1, Proc. Acad. Nat. Sci. Phila., 

 vol. 63, p. 360. 



This common and well-known species has been recorded by 

 Brown and Pilsbry from the Canal Zone. We have a single spec- 

 imen from Water Cay, found in the interior of the specimen of 

 Solenosteira Vaughani var. medioajuericana. This species first 



