60 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



whorl, and many very fine, faint, wavy spiral striations; surface 

 covered by a thin epidermis. Columella usually somewhat flexuose. 



Type. — Pyrgolampros mioperplicatulus Sacco. 



All our west American species are of a light-yellow to chocolate- 

 brown color. The intercostal spaces are not depressed as in Chem- 

 nitzia, but appear as simple shallow undulations between the axial 

 ribs. The spiral striations, in perfect specimens, appear as if they 

 were situated beneath a light-colored epidermis and were shining 

 through it. 



KEY TO THE SPECIES OF THE SUBGENUS PYROOLAMPROS. 



Axial ribs well developed. 

 Shell short and stout. 

 Shell unicolor. 



Whorls excurved at the summit victoriana, p. 61. 



Whorls not excurved at the summit. 

 Shell brown. 



Axial ribs 12-lG gibhom, p. 61. 



Axial ribs 18-20 ridgwayi, p. 62. 



Shell light fulvous valdezi, p. 62. 



Shell banded newcombei, p. 63. 



Shell elongate-conic. 

 Shell unicolor. 



Shell large, adult more than 10 mm. long tai/lori, p. 64. 



Shell smaller, adult less than 8 mm. long. 



Whorls well rounded luwei, p. 64. 



Whorls flattened. 



Axial ribs strong, acute hallbrecta, p. 65. 



Axial ribs weak, rounded gouldi, p. 66. 



Shell bicolor. 



Spire golden yellow, base white aurantia, p. 66. 



Posterior two-thirds between the sutures light brown, anterior third and 



base darker ■. pedroana, p. 67. 



Shell banded. 



Band single, broad, extending over the periphery and to both sides of it. 



Shell large, adult more than 8 mm. long halia, p. 68. 



Shell small, adult less than 6 mm. long lyalli, p. 68. 



Bands double. 



Bands lighter than rest of shell berryi, p. 69. 



Bands darker than rest of shell ulaskana, p. 70. 



Bands triple. 



Bands not visible on the spire only in the outer lip. .chocolata, p. 70. 

 Bands visible on the spire. 



Axial ribs on penultimate whorl 22 painei, p. 71. 



Axial ribs on penultimate whorl 30 keepi, p. 71. 



Axial ribs poorly developed on the early whorls, never indicated on the later ones. 



Shell dark brown with a narrow lighter band halistrepta, p. 72. 



Shell wax yellow with a light brown peripheral zone. 



Shell large, adult more than 11 mm. long lituyana, p. 73. 



Shell smaller, adult less than 9 mm. long , oregonensis, p. 73. 



