NO. 2 PYRAMIDELLID MOLLUSKS — BARTSCH 37 



The type, U.S.N.M. No. 561696, comes from the PHocene of North 

 St. Petersburg, Fla. It has 6^ postnuclear whorls and measures: 

 Length 2.3 mm., diameter 0.8 mm. 



I take pleasure in naming the species for John Parker, who made 

 all the drawings accompanying this paper. 



Genus PYRGISCUS Philippi 



1841. Pyrgiscus Philippi, Wiegmann's Arch. Naturg., vol. 7, pt. i, p. SO (type: 



Melania rufa Philippi). 

 1843. Ortostelis Aradas and Maggiore, Atti Accad. Gioenia Sci. Nat. Catania, 



vol. 20, p. 117 (same type). 

 1884. Pyrgostelis Monterosato, Nomenclature generica e specifica di alcune 



Conchiglie mediter ranee . . ., p. 89 (same type). 



Pyramidellids having prominent axial ribs and deeply incised spiral 

 lines, but no varices or internal lirations on the outer lip. Columella 

 usually somewhat flexuous. 



Type: Melania rufa Philippi. 



KEY TO THE SPECIES OF PYRGISCUS 



Incised spiral lines 4 ycimai 



Incised spiral lines not 4. 

 Incised spiral lines 5. 



Axial ribs fine and closely spaced sethusi 



Axial ribs not fine or closely spaced. 



Whorls strongly rounded vishnui 



Whorls not strongly rounded. 



Axial ribs very strong and distantly spaced vemisae 



Axial ribs not very strong and not distantly spaced, tityusi 

 Incised spiral lines not 5. 

 Incised spiral lines 6. 



Axial ribs very strong and widely spaced. 



Shell broadly conic thestiusi 



Shell not broadly conic, slender. 



Incised spiral lines of uniform strength tellusae 



Incised spiral lines not of uniform strength clionae 



Axial ribs not very strong and less widely spaced. 



Whorls strongly rounded tantalusi 



Whorls not strongly rounded. 



Whorls only moderately rounded sylvanusi 



Whorls not moderately rounded, flattened. 

 Shell large. 



Shell stout somnusi 



Shell slender sisyphtisi 



Shell small. 



Axial ribs fine silenusi 



Axial ribs not fine but strong pyrrhusi 



