Class GASTROPODA 



order OPISTHOBRANCHIATA 

 Suborder TECTIBRANCHIATA 



Family ACTEONIDAE 



Genus ACTEON Montfort 



rConch. Syst., vol. ii, 1810, p. 314] 



Type. — Toluta tomcealis Gnielin. 



Shell thin, ovate; spire usually prominent, acutely tapering; nucleus 

 rather small, twisted, heterostrophous ; principal sculpture spiral; aper- 

 ture entire, elongate; rounded anteriorly; columella furnished with a 

 single, slightly oblique plication ; umbilicus imperforate. 



The genus is indicated in the Triassie and reached its maximum develop- 

 ment in the Eocene, though it persisted with diminished prominence 

 through the later Tertiary and to the present day. The living species, 

 though comparatively few in number, have a wide geographic range. 



A. Whorls very broadly convex; spiral sculpture uniform in character 



over the entire external surface Acteon linteus 



B. Whorls flattened laterally; cylindrical; exceedingly slender; spiral 



sculpture evanescent on the posterior portion of the whorls. 



Acteon gabbana 



Acteon linteus Conrad 



Plate XVIII, Figs. 3, 4 



Solidulus linteus Conrad, 1858, Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iii, 

 p. 334, pi. xxxv, fig. 10. 



Description. — " Elliptical, with very numerous close revolving lines, 

 most distinct on the inferior half; interstices regularly and elegantly 

 striated transversely. A beautiful species, but the specimen much dis- 

 torted, which I have endeavored in the figure to restore to something of 

 its original shape." — Conrad, 1858. 



Etymology: 'iKraiov, dwelling on the coast. 



26 



