ACT.EONINA. 173 



8hell shaped like Actjeon, imperforate, oval or fusiform, with the 

 spire prominent, but shorter than the last whorl. Whorls angular 

 or channelled in the vicinity of the suture. Aperture long and nar- 

 row, rounded at base, the columella concave, somewhat thickened, 

 without folds or teeth. Type A.carhonaria Kon. 



This genus was proposed for fossil forms having the contour of a 

 slender, long-apertured Adceon, but without folds upon the colum- 

 ellar lip. Orbigny claims the date 1847 for Acfceonina, but it was 

 not actually published in that year. See Prodr. Pal. Strat. Univ., 

 i, p. lix. The genus has been restricted by Meek, who removed 

 from it the peculiar groups C'o?iaeteo?i and Enconackwn. The typical 

 forms extend from the Carboniferous to the Portlandian formation. 



The two recent species referred to the genus are to be regarded 

 as. very doubtful members of it. They are more likely to be an in- 

 dependent group of foldless Admonidae near Bullina, than descend- 

 ants of this long extinct genus, the shells of which have a Jades 

 quite different. 



A. EDENTULA Watsou. PI. 49, figs. 12, 13. 



Shell fragile, ovate, white, with a thin, chestnut-colored epider- 

 mis, a bluntish scalar spire, a largish mouth, inner lip untoothed. 

 Sculpture : Longitudinals — there are very many close set minute 

 lines of growth, with here and there one much stronger than the 

 rest, which cuts in like a fault on the spirals, interrupting their con- 

 tinuity. Spirals — there are many regular, but not sharp-cut nor 

 stippled furrows which corrugate even the interior surface of the 

 shell : about 70 of these are on the body ; about 20 on the penulti- 

 mate whorl. They are strongest toward the middle of the body- 

 whorl, and somewhat faint toward the upper suture ; the flat surface 

 between them which is about thrice their breadth, is more or less 

 distinctly scored by a very faint furrow. Color opaque white, 

 covered with a thin, glossy chestnut-colored epidermis, which is a 

 little darker below the suture and on the base. Spire rather high, 

 roundedly and bluntly conical, scalar. Apex slightly eroded, 

 but evidently blunt, large and slightly inverted. AVhorls 5*,' 

 somewhat convex, of rather rapid but regular increase ; the last 

 is long and cylindrical, with a rounded produced base. Suture 

 oblique, strong; axially impressed rather than channelled. Mouth 

 long, transversely pear-shaped, narrowing very gradually above, 

 open and rounded below. 



