410 Systematic Paleontology 



ACTEOCINA EORBESIASTA (Whitfield) 



Tornatella Forbes, 1845, Quart. Jour. Geol. Soc, London, vol. i, p. 63, fig. c. 

 Actwon forbesiana Whitfield, 1892, Mon. LT. S. Geol. Survey, vol. xviii, p. 



157, pi. xix, figs. 17-22. 

 Actwon cretacea Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, p. 



805. (Synonomy and figures excluded.) 



Description. — ■" Shell of about a medium size for the genus, broadly 

 ovate or ovoid in outline, spire short, obtusely rounded, middle portion of 

 the shell subeylindrical and the base obtusely pointed, having nearly the 

 same angle as that of the spire. Volutions from four to five in number, 

 closely coiled and rising but slightly one above another ; body volution very 

 slightly chamfered just below the suture, presenting an almost impercept- 

 ible angle a little below the suture, below which it is nearly cylindrical to 

 below the middle of its length, and obtusely pointed at the lower extremity. 

 Aperture two-thirds the length of the shell, and considerably longer than 

 the diameter of the body volution, very narrow at the upper part, but 

 gradually widening below, rounded in front. Columella comparatively 

 strong, bearing a single oblique ridge near the middle of its length, and 

 having the margin thickened below it and around the base of the aperture, 

 as seen by the impression of these features on the internal casts. Surface 

 of the casts marked by rather fine, closely arranged, spiral lines, which 

 may have been punctate on the shell, as on one of the casts there are indi- 

 cations of such a feature having existed ; this, however, is by no means 

 certain. No transverse markings, other than perhaps fine lines of growth, 

 are indicated on any of the specimens present. 



" The species differs from any of the associated forms in the propor- 

 tions of the shell, being much more robust than in Acteon gabbano,, and 

 much less so than A. bullata. In fact it is of a very different type from 

 the latter species. It bears some relation to Acteon ovoidea Gabb, but is 

 a much shorter and smaller species, and has been entirely destitute of the 

 broad longitudinal ribs credited to that one; nor has it had a second fold 

 on the columella in advance of a ' large broadly rounded ' one as described 

 on that shell, the fold being quite faint and slight on all the specimens 

 examined. The figure given by Lyell and Forbes above cited is quite (bar- 



