Page:American Seashells (1954).djvu/198

148 6.0 mm. in length. Color pinkish brown to chalky-white with occasional darker brown mottlings. With about 100 fine, squarish, closely set axial rings. Plug with a rather long, oblique spur. Spur sometimes eroded down to a small sharp pimple (form oregonense Bartsch). Irregularities occur in the expansion of the tube; sometimes there is a more rapid expansion toward the anterior end (forms named as species: C. pedroense Bartsch and C. barkleyense Bartsch). C. catalinense Bartsch is probably this species, since many of the paratypes do not have the anterior end supposedly “bulbously expanded,” and many specimens have about too axial rings, and not 75 as claimed. C. rosanum Bartsch appears to be a very long specimen (7 mm.) with sharply defined rings. Common.

3 to 5 mm. in length, white, with axial rings and longitudinal ribs. One species in southern California and 3 or 4 in the Western Atlantic. They resemble minute scaphopods, but are distinguished from them by the apical plug and small size of the shell.

4 to 5 mm. in length, slender, glossy, opaque-white; with about 15 strong, longitudinal ribs. Avxial, raised rings are prominent near the aperture and sometimes give the shell a cancellate appearance at the anterior end. Apical plug with a fairly long, pointed prong. Common.

3.5 to 4.8 mm. in length. First half to first $3/4$ of shell smooth, but at the apertural end developing about a dozen small, sharply defined axial rings. Longitudinal sculpture microscopic or absent. Color translucent-white to gray. This species is doubtfully placed in this subgenus.

2.0 to 2.5 mm. in length. Opaque-white. 7-sided in cross-section. The 7 longitudinal ribs are strong, raised, and the spaces between them are flat or slightly concave. There are about 30 deeply cut circular lines around the