373 



Costa Rica Miocene— Olsson 



lOI 



last are in the form of broad, subobsolete, smooth bands without 

 the sculptured interspaces; there are about 15 spiral cords on 

 the last whorl in addition to those of the anterior canal; anterior 

 canal of moderate length, strongly twisted; columella with 4 

 plaits, heaviest above; aperture narrow. 



Length 74 (apex broken), diameter 23, last whorl 52, 

 spire 35 mm. 



A single, large shell with rudely sculptured whorls was col- 

 lected from the coralline limestone near Port Limon. It agrees 

 closely with Reeve's figure of Mitra Szvainsoni, except that the 

 spiral bands are larger and heavier. 



The Mitra Sivaijisoni is a West Coast shell belonging to the 

 Panamic province. It is distinguished b}' its large size, rudely 

 sculptured whorls and dark colored epidermis. Dall has des- 

 cribed as the variety afitille?isis , specimens dredged off of Cape 

 lyookout, N. C, Colombia and Yucatan. 



Gatun Stage: Port Linio7i. 



Mitra longa Gabb Plate 6, figure 10 



Mitra longa Gabb, 1873. Trans, Amer. Phil. Soc, vol. 15, p. 219. 

 Mit7^a longa Brown and Pilsbry, 191 1, Proc. Acad. Nat. Sci. Phila., vol. 



63, p. 346, pi. 24, fig. II. 

 Mitra longa Maury, 1917, Bull. Amer. Pal., vol. 5, p. 238, pi. 11, figs. 



II, iia. 



A long, slender species, sculptured with strong, revolving 

 cords and fine, neatly engraved interspaces. We have collected 

 this Dominican species only in the Canal Zone. The figured spec- 

 imen has the following dimensions: 



Length 40, diameter 10.5, last whorl 26, spire 21 mm. 

 Gatu7i Stage: Gatun, C. Z. 



Mitra Ciariensis Brown ond Pilsbry Plate 6, figure 25 



Mitra dariensis Brown and Pilsbry, 191 1, Proc. Acad, Nat. Sci. Phila., 

 vol. 60, p. 346, pi. 24, fig. II. 



