1917.] NATURAL SCIENCES OF PHILADELPHIA. 299 



One of these occurs in the Aachen Cretaceous of Vaals, Germany, 

 and was described in 1851 by Miiller, and referred to the genus 

 Tritonium;^^ the other is a closely related form from the Msestrichtian 

 of Belgium which Kaunhowen^'^ compares with Miiller's species from 

 Vaals, but does not apply a name to it. Astandes differs from Trito- 

 nium or Nyctilochus in lacking of true varicose axials and in a shorter 

 and much less strongly developed anterior canal. 



Astandes densatus n. sp. PI. XVII, figs. 7, S. 



Descrijjtion. — Shell small and nearly trochoid in outline; spire 

 moderately elevated and more than half the length of the entire 

 shell; protoconch small and smooth; whorls of conch six in number, 

 circular in cross-section and increasing in size gradually; external 

 sculpture both axial and spiral; axials fairly coarse, well rounded 

 and retractive, evanescing on the base of the body; axials overridden 

 by numerous elevated spiral lines; aperture D-shaped, produced 

 anteriorly into a short shallow canal; outer lip slightly thickened and 

 dentate; parietal wall washed with a callus. 



Dimensions. — Altitude 11.5 mm.; maximum diameter 7 mm. 



This species is characterized by the elevated spiral lines which 

 override the protractive axials and further by the dentate outer lip. 

 It is represented in the present collection by several individuals. 

 No closely related American species is known, but the Tennessee 

 form may be compared with the Maestrichtian species Tritojiium cf. 

 cretaceum (Miiller) Kaunhowen/'^ which reseml)les it very much in 

 form of aperture and character of external ornamentation but differs 

 in details of external sculpture. 



Family SOALID^. 

 Genus ACIRSA Morch. 

 Acirsa microstriata n. sp. PI. XVIII, fig. 8. 



Description. — Shell of medium size, thin and strong; form an 

 elongate, simple, slender cone; spire acuminate; volutions eleven on 

 the type individual which has the apical tip broken away, probaljlj^ 

 fourteen on the original, whorls increasing regularly in size from apex 

 to ultima, volutions flattened laterally, penultima and ultima very 

 slightly constricted toward the sutures; protoconch unknown; 



^* Tritonium cretaceum Holzapfel, 1888, Paloeontographica, Band xxxiv, 113, 

 Taf. X, figs. 5-7. 



'9 Kaunhowen, F., 1897, Pal. Abhandl, Acht. Bd., p. 77, Taf. ix, figs. 4, 4a; 

 Taf. xiii, Fig. 12. 



*o Kaunhowen, F., 1898, loc. cit. 



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