74 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



The tj^e has 8^ whorls remaining which measure: Length 8.5 mm., 

 diameter 2.7 mm. It and another specimen (Cat. no. 181112, 

 U.S.N.M.) were dredged by the U. S. Bureau of Fisheries steamer 

 Albatross at station 2885, off Oregon, in 30 fathoms, with a liottom 

 temperature of 49°. 



Another specimen (Cat. no. 196222, U.S.N.M.) was dredged at 

 station 2868, off the coast of Washington, in 31 fathoms, on gray sand, 

 with a bottom tem])erature of 46.9°. 



Subgenus PYRGISCUS Philippi. 



Pyrgiscus Philippi, Wieg. Arch., vol. 1, 1841, p. 50. Type, Melaniarufa Philippi= 

 Pyrgostelis Monterosato, Conch. Medit., 1884, p. 89, same tjpe=Ortostelis 

 Aradas, Atti Dell Acad. Giov. di Catania, 1843, vol. 20, same type. 



Turbonillas having prominent axial ribs and deepl}^ incised spiral 

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

 usually somewhat flexuous. 



Type. — Melania rvfa Philippi. 



KEY TO THE SPECIES OF THE SUBGENUS PYRGISCUS. 



Base without spiral sculpture. 



Shell with a tuberculate cord near the summit annettx, p. 76. 



Shell without tuberculate cord near the summit gracillima, p. 77. 



Base with spiral sculpture. 



Axial ribs terminating abruptly at the periphery. 

 Shell broadly conic. 



Incised spirals between the sutures 6 of uniform strength.. vexativa, p. 77. 

 Incised spirals between the sutures 7 not of uniform strength. o6esa, p. 78. 

 Shell elongate-conic. 



Incised spirals between the sutures of uniform strength favilh, p. 78. 



Incised spirals between the sutures not of uniform strength. 



Spiral lines 5 strong and 3 slender pcquensis, p. 79. 



Spiral lines 7 strong and 6 slender nuttingi, p. 79. 



Spiral lines 2 strong and 11 slender callia, p. 80. 



Spiral lines 2 strong and 20 slender superba, p. 80. 



Axial ribs passing feebly over the periphery, but evanescing before they reach 

 the middle of the base. 



Shell stout and very robust. 



Axial ribs somewhat tubercuiate pluto, p. 81. 



Axial ribs not tuberculate jeivetii, p. 82. 



Shell broadly conic. 



Incised spiral lines between the sutures of uniform strength. 



Incised spirals between the sutures 6 signse, p. 83. 



Incised spirals between the sutures 7. 



Intercostal spaces about as wide as the ribs striosa, p. 83. 



Intercostal spaces double the width of the ribs. 



Base with 13 well-incised spiral lines only... morchi, p. 84. 

 Base with 15 well-incised lines and narrow 



spiral striations nragoni, p. 85. 



Incised spirals between the sutures 8 recta, p. 85. 



