ART. 22 MIOCENE GASTROPODS AND SCAPHOPODS MANSFIELD 39 



Dimensions: Figriired and only specimen (U. S. Nat. Miis. Cat. No. 

 352653) measures : Length 36 mm.; greatest diameter 21 mm.; length 

 of aperture 30 mm. 



The shape of the species recalls Marginella aurora Dall from the 

 Chipola River, Florida, but the Chipola species has a narrower 

 aperture and a denticulated outer lip along its inner margin. 



Occurrence. — Upper Miocene: Springvale, near Couva, Trinidad, 

 British West Indies. 



MARGINELLA CALYPSONIS Maury 

 Plate 0, fig. 11 

 Manrlnclla calypsonis Mauky, Bull. Anier. Paleont., vol. 10, no. 42, p. 199, pi. 

 34, figs. 12, 13, 1925. 

 Shell of medium size, ovatecylindrical, solid, polished, and about 

 four whorled. Spire low, extending 3 mm. above the outer lip, 

 partly concealed by callus; body whorl on the dorsal side of the 

 shell, ovate with the periphery at the posterior one-third of its 

 length; in front, the shell is slightly flattened and covered by a 

 thick wash of callus : on the left side this callus forms a low rounded 

 shoulder, and posteriorly nearly overlaps the spire and then encir- 

 cles the aperture and extends a little below the shoulder of the 

 whorl. Aperture moderately narrow, linear, and a little wider be- 

 low; outer lip nearly straight, outer margin with a strong, distinct 

 varix, inner margin smooth. Columella slightly concave, provided 

 with four rounded, nearly equal-sized plications— the posterior two 

 are transversely placed, the anterior two oblique. 



Dimensions : Figured specimen (U. S. Nat. Mus. Cat. No. 352654) 

 measures : Length 20 mm. ; greatest diameter 11 mm. ; length of aper- 

 ture 17 mm. 



The nearest fossil ally to the species is Marginella inacdonaldi 

 Dall, a species recorded by Olsson,^^ who writes : 



" This large Marginella is one of the most common and charac- 

 teristic species of the Gatun beds of Costa Rica." Marginella moxi- 

 donaldi, however, is a larger shell with a proportionately shorter 

 spire and a more expanded aperture at the posterior extremity. 



The nearest recent ally, and, indeed, a very similar species is Margi- 

 nella cincta Kiener. Marginella cincta is a proportionately broader 

 shell, and has a more abrupt and steeper shoulder on the body whorl. 

 Occurrence. — Upper Miocene: Springvale, near Couva, Trinidad, 

 British West Indies. 



MARGINELLA SOLITARIA MONTSERRATENSIS, new subspecies 



Plate 6, figs. 5, 6 

 The new subspecies differs from Marginella solitaria Guppy ^■^ 

 from the Ditrupa bed, Point-a-Pierre. Trin idad, in the following re- 



13 Bull. Amer. Paleont., vol. 9, p. 267, 1922. 



" Proc. U. S. Nat. Mus., vol. 19, p. 308, pi. 29, fig. 14, 1896. 



