399 Costa Rica Miocene — Olsson 127 



ly distantly raised into small, longitudinal plicae which is most 

 characteristic. An average specimen from the Canal Zone will 

 measure: 



Length 25, diameter 10, spire 13, aperture 12.50 mm. 



We collected from the lower Gatun sandstones of Codes 

 Creek, near Old Harbor, Costa Rica, several small Strombinas 

 which except for size are typical Lessepiana. 



Gatun Stage: Gatun and Mt. Hope, C. Z. 

 Codes Creek, C. R. 



Strombina matima, n. sp. Plate 10, figure 7 



Shell ovate, moderately solid with a long evenly tapering and 

 sharp-pointed spire; nucleus small, pointed and of three, smooth 

 whorls; post-nuclear whorls 6; suture distinct and bordered an- 

 teriorly by a small sutural ridge; the sculpture consists of about 

 18, smooth, narrow ribs, which are lacking from the back of the 

 last whorl, which is smooth; the ribs are oblique in direction and 

 along the upper sutures are slightly knobbed by the sutural ridge; 

 the base of the last whorl and canal carries about 12 spirals; aper- 

 ture subelliptical with a heavy outer lip internally provided with 

 3 or 4 denticles about the middle; anterior canal straight and 

 smooth within. 



Height 12, diameter 5.25, aperture 6 mm. 



This is a species with a long, evenly-tapering spire and 

 small nucleus. The spire-whorls are sculptured with numerous, 

 small, smooth riblets. The riblets are obsolete on the back of 

 the last whorl which is entirely smooth except for the spirals 

 about the base and canal. ►$". viatima resembles 6". Bassi Maury, 

 from the Miocene of Santo Domingo but is more slender and has 

 a great many more ribs. 



Gatun Stage: Hill la, Ba7iana River. 

 Coll. 7, Estrella River. 



Strombina cricamola, n. sp. Plate 10, figure 18 



Shell ovate, solid, with a large, convex and spirally sculp- 



