295 Costa Rico Miocene — Olsson 123 



Genus ALECTRION Montfort 

 Alectrion ranwncula, n. sp. Plate 9, figures 20, 22 



Shell of medium size, with a large body-whorl and a sharp 

 pointed spire; the general form and sculpture recalls the recent 

 A. acuta Saj-; spire about the same length as the aperture and 

 canal and composed of about 7 whorls, of which the first 2 belong 

 to the small, smooth nucleus; the profile of the spire-whorls is 

 convex with deep, excavated sutures; sculpture of narrow ribs, 

 the tops of which are crossed by spirals and separated by wide, 

 smooth interspaces; the last whorl has about 9 ribs which are 

 large and humped on the ventral face, finer and more numerous 

 on the back; there are 3 spirals on the spire-whorls and 7 on the 

 last with several more on the short canal; aperture subcircular 

 with a large, heavy outer lip, internalh' denticulated. 



The general form and sculpturing recalls the recent East 

 Coast Alectrion acuta Saj^, but the Costa Rican shell is much 

 broader as indicated hy the following comparative measurements 

 with A. acuta Saj^, of the same height. 



Height 14.00, diameter 6.25, last whorl 8, aperture 6 mm. 



{Alectrion acuta Say) 

 Height 14.50, diameter 8.25, last whorl 9, aperture 7.5 mm. 



{Alectrion ranuncula^ n. sp.) 

 It is not uncommon in the Gatun beds of the Banana 

 River. 



Gatu?i Stage: Hill la, Ba7iana River. 

 Coll. 7 Estrella. 



Alectrion losquemadica Maury Plate 9, figure 21 



Alectrioti losquemadica Maur}-, 1917, Bull. Amer. Pal., vol. 5, p. 255, 

 pi. 15, figs. 22, 23. 



The Costa Rica fossil is similiar in its sculpturing and form 

 to the common recent West Indian A. ambigua Montfort. As 

 Maur}^ has pointed out in regard to the Dominican examples, the 



