266 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Fossil: Miocene. 
Described as Nassa cooperi. 
Alectrion cerritensis Arnold, 1903 
Paleontology of San Pedro, California, 231; PI. 4, fig. 1. 
Shell small, conical; spire elevated; apex subacute; whorls eight, 
slightly convex, crossed by seven to ten prominent, rounded ridges which 
are less prominent near the suture; spiral sculpture consists of nine to 
eleven sharp, raised lines; three upper whorls have a cancellate appear¬ 
ance ; suture appressed, wavy; aperture ovate; outer lip thickened by den¬ 
ticulated ridge on inner side; inner lip smooth, incrusted, the incrustation 
completely covering the spiral sculpture internally; columella twisted, 
spirally sculptured, with deep groove next to body-whorl; canal short, 
broad, recurved. Long., 30; lat., 14.5; body-whorl, 18; aperture, 11 mm. 
(Arnold.) 
Type in United States National Museum. Type locality, Upper San 
Pedro, series at Los Cerritos. 
Range. Long Beach, California, to Gulf of California; also Pliocene. 
Alectrion perpinguis Hinds, 1844 
Plate 26, fig. 11 
Zoology of the Voyage of H.M.S. Sulphur, 36; PI. 9, figs. 12, 13. 
Testa elongata ovata, acuminata, lutescente, tenui; anfractibus senis 
rotundatis, ventricosis, cancellatis, concoloribus vel pallide fasciatis, ultimo 
parviusculo; columella vex callosa. (Hinds.) 
Shell small, conical; spire elevated; apex subacute; whorls seven, 
convex, abruptly truncated at posterior margin, forming a spiral table; 
ornamentation consists of sharp, spiral ridges with slightly wider inter¬ 
spaces, and posteriorly sloping transverse ridges, the whole giving a de¬ 
cidedly cancellate appearance to the surface; suture deeply impressed, 
distinct; aperture subovate; inner portion of aperture ridged by spiral 
sculpture; outer lip thin; inner lip thinly incrusted; columella twisted 
and spirally ornamented; groove on upper part of columella prominent; 
canal short, curved. Length, 23; height, 12.3; body-whorl, 15; aper¬ 
ture, including canal, 11 mm. (Arnold.) 
Type in Zoological Museum, Copenhagen, lype locality, Bay of 
Magdalena, Lower California. 
Range. Puget Sound to Cerros Island, Lower California. Fossil: 
Pleistocene—Santa Barbara to San Diego, California. Pliocene—San 
Diego well, San Pedro, California. Miocene—Santa Monica and Aliso 
Creek, Los Angeles County, California. 
[ 266 ] 
