ART. 5 NEW FOSSIL MOLLUSKS MARSHALL, AND BOWLES 3 



The material filling the shells and molds of the fresh-water mussels 

 and the mold of Pomacea {Ampullaria) is a light-gray calcareous 

 sandstone. The surface of these specimens is yellowish brown, owing 

 to a ferruginous-clay stain. The matrix of the Sheppardiconcha and 

 the Potamolithoides is the same calcareous sandstone mentioned 

 above, but the surface is grayish white, with little of the ferruginous 

 stain. The grayish sandstone in the single valves of the mussels con- 

 tains fossils and imprints of the shells of Sheppardiconcha^ which, 

 when they occur thus, are lightly coated with the ferruginous stain. 



SHEPPARDICONCHA, new genus 



Fresh-water gastropod mollusks with turritelliform spire, roundish 

 aperture, which apparently is somewhat produced at the columellar 

 side. 



Type species. — Sheppardiconcha hlhllana, new species, described 

 in this paper. 



Beinarks. — This genus differs from Hemlsinus Swainson in the 

 turritellalike spire and in the rounded aperture. In Hemlsinus the 

 aperture is elongate and has a distinct anterior canal, making some 

 of the species, notably the type, Hemlsinus llneolatus Wood, resemble 

 a very elongate Planaxls. Hemlsinus tuber cull ferus Conrad is not 

 a Hemisinus, but belongs in Sheppardiconcha. Hemisinus steeri 

 Conrad is apparently properly placed in the genus Hemisinus. 



SHEPPARDICONCHA BIBLIANA, new species 



Plate 1, Figure 6 



Shell turritelliform, imperforate, whorls numerous, slowly in- 

 creasing in size, somewhat flattened. Longitudinal sculpture con- 

 sisting of sinuous, slightly protractive incremental striae. Spiral 

 sculpture of five strong, obscurely nodulous lirae on the surface of 

 the whorls of the spire and one sunk in the suture. The upper lira 

 and the one just above the suture a little stronger than the others and 

 forming between them a deep channel marking the suture. Base 

 worn but showing the remains of several lirae. Aperture roundish, 

 columella curving forward. 



Type. — U.S.N.M. No. 372837 measures : Length (upper whorls 

 missing) , 20 mm ; diameter, 8.5 mm. It and a number of paratypes 

 (U.S.N.M. No. 372838) come from Biblian, Province of Canar, Ecua- 

 dor. U.S.N.M. No. 372839 includes a large number of specimens 

 from Paccha, Province of Azuay. 



Remarks. — The strildng features of this species are the turritella- 

 like form, the deeply channeled sutures, and the spiral lirae. It is 

 related to " Hemisinus " tuberculiferus Conrad, of the Pebas group 



