298 PROCEEDINGS OF THE ACADEMY OF [Sept., 



regularly in size from the apex to the ultima; protoconch not dis- 

 tinctly separate from the conch, consisting probably of three volu- 

 tions which slope less steeply than do those of the conch; external 

 surface highly polished; sculpture absent, excepting for very fine and 

 crowded spirals and faint incrementals, discernible with a lens in the 

 glaze of the external surface; suture indicated by a simple slightly 

 impressed spiral line; body abruptly constricted in front of the 

 periphery and produced into a narrow recurved pillar; aperture 

 lenticular; terminating anteriorly in a narrow, rather long, recurved 

 canal; outer lip thin and simple; inner lip excavated medially, washed, 

 with a thin callus; columella smooth. 



Dimensions (slightly imperfect individual). — Altitude 76.2 mm.; 

 maximum diameter 22.5 mm. 



This species is the type of the genus and is well characterized by 

 its broad, flat whorls and the fine, crowded spiral lines that show 

 through the glaze of the external surface. The shells are relatively 

 thick but not strong. They are fairly common at Coon Creek, but 

 so fragile that not a single perfect specimen has as yet been recovered 

 from the sediments. 



Genus ASTANDES n. gen. 



Etymology: 'AaTdv8rj<i^ a messenger. 



Type: Astandes densatus n. sp. 



Shell small and trochoid in outline; aperture of the type specimen 

 less than half the entire length of the shell; protoconch small, smooth 

 and trochoid; whorls of conch circular in cross-section and increasing 

 gradually in size; external sculpture both axial and spiral, axials well 

 rounded and retractive; spirals lirate; suture impressed; body equally 

 constricted in front and behind; aperture D-shaped and produced 

 in front into a short shallow canal; outer lip thickened and dentate; 

 parietal wall washed with a callus; umbilicus imperforate. 



This genus is very much like Cerithioderma Conrad^® in general 

 outline, the circular cross-section of the whorls and in the axial and 

 spiral sculpture, but differs from it in the less acuminate spire and 

 the imperforate umbilicus. It resembles Paladmete Gardner,^^ but 

 differs from that group in having a short anterior canal. The genus 

 is proposed to include a species recently discovered at Coon Creek 

 and two other known species in the European Upper Cretaceous. 



3" Conrad, T. A., 1860, Jour. Acad. Nat. Sci. Phila., 2d ser. Vol. IV, p. 295, 

 PI. 47, fig. 30. Cossmann, lyl., 1906, Ess. de Pal. Comp., livr. VII, p. 191. 



" Gardner, J. A., 1916, Md. Geol. Survey, Upper Cret., p. 412, PI. XVIII, 

 fiss. 14, 15. 



