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158 American Seash ells
Base of shell with 2 large, smoothish, spiral cords. C. grippi Bartsch and
C. pedroana Bartsch are possibly dwarf forms of this species whose beaded
sculpture is more variable than is generally suspected.
Genus Seila A. Adams 1861
Shell small, very slender, whorls flat-sided, nucleus glassy-smooth and
of about 3 whorls. Small, short siphonal canal. Sculpture of strong spiral
cords between which lie microscopic axial threads.
Seila adamsi H. C. Lea Adams' Miniature Cerith
Massachusetts to Florida, Texas and the West Indies.
Plate 2 2t
/4 to /4 inch in length, resembling a miniature Terebra, with about
a dozen whorls. Long, slender, flat-sided, dark-brown to light orange-brown
in color, and characterized by 3 strong, squarish, spiral cords on each whorl
(4 on the last whorl). Occasionally with minute axial threads showing between
the spiral cords. Base of shell smoothish, concave. Outer Hp fragile,
wavy and sharp. Suture indistinct. This is S. terebralis C. B. Adams. Common
from shore to 40 fathoms.
Seila monterey ensis Bartsch Monterey Miniature Cerith
Monterey, California, to the Gulf of California.
% to /4 inch in length, yellowish to reddish brown. Whorls and spire
flat-sided. Whorls in spire with 3 raised, flat-topped, evenly spaced, smooth
cords between which are numerous, microscopic, axial threads. Last whorl
with 5 cords. Base smoothish, concave. Common from low tide to 35 fathoms.
Genus Alabma Dall 1902
Shell small, slender. Nucleus slender, of 3 to 4 glassy, smooth whorls.
Aperture subcircular. Lower part of the outer lip extended and flaring.
Umbilicus very narrow and very small. With obscure, narrow, curved axial
ribs and prominent spiral threads. This genus is put in the family Diastomidae
by some workers.
Alabifia tenuisculpta Carpenter Sculptured Alabine
San Pedro, California, to Lower California.
/4 inch in length, slender, 8 to 9 whorls, ashen gray with a light-brown
undertone. Outer lip thin; umbilicus small. Spiral sculpture of 4 to 6 weak