JUL 7 1922 



MOLLUSCA 



CLASS GASTROPODA 

 ORDER OPISTHOBRANCHIATA 



SUBORDER TECTIBRANCHIATA 



Genus ACTAEON, Montfort 



Actaeon costaricensis, n. sp. 



Shell moderately large, ovate-cylindric; body-whorl large 

 and more than ^ of the total length of the shell; spire pointed, 

 conic; whorls about 6, convex and with deep sutures; spiral 

 sculpture of fine, nearly regular, smooth threads separated by 

 deep and somewhat wider interspaces; there are about g spiral 

 threads on the spire- whorls and about 34 on the last whorl; the 

 interspaces are crossed by fine, elevated, distant threads; aper- 

 ture linear-lanceolate, rounded below; columella with a single 

 large fold. 



Height 19.5 mm, diameter 10 mm, aperture 14. 5 mm. 



This is an unusually large and cylindrical species with a 

 relatively high spire. Suggestion of the original coloration is 

 indicated by a white band which encircles the middle of the 

 last whorl commencing at the upper end of the aperture, — the 

 general ground-color of the surface being a faint purple or red- 

 dish brown. The interspaces between the spirals are crossed by 

 fine, elevated threads, but they appear merely punctate on the 

 early whorls. 



Gatun Stage: Hill No. j, Banana River. 

 Middle Creek. 



Genus ACTEOCINA, Gray 



Acteocina buHata Kiener, var. costaricana, n. var. Plate 15 figures 20, 11 



cf. Tornatina bullata Kiener, Icon. Coq. Viv., p. 5, pi. i, fig. 4. 



206a ~ 34^; 



