Page:American Seashells (1954).djvu/171

Rh should be considered a typical Tegula. Moderately common, especially in the north.

1 to $1 1/4$ inches in length, about as wide. Conical in shape, with very flat-sided whorls and spire. Base almost flat. Surface smoothish, except for almost obsolete spiral threads. Umbilicus very deep, lined with 1 or 2 weak spiral cords. Columella arched, and with 1 prominent, pointed tooth. This rather rare species resembles a large Calliostoma. It is found on kelp in moderately deep waters.

The operculum in members of this subfamily is round, multispiral, and with a horny base on top of which are numerous rows of tiny calcareous beads.

$1/2$ inch in diameter, flat-topped, 4 whorls, opaque-white. Widely and deeply umbilicate. Axial sculpture of 15 to 17 rounded, low ribs which encircle the entire whorl and are made nodulose in crossing the 12 smaller spiral cords. Periphery squarish, with a cord above, below and at the center. Rare from 1 to 17 fathoms. Cyclostrema is a neuter, not feminine, word. C. amabile Dall from Cuba to Barbados is much rarer and differs in being smaller, in having a thicker, more rounded lip, and in lacking axial cords on top of the whorls. 25 to 80 fathoms.

$1/4$ inch in length, not quite so wide; thick, rose in color. Whorls globose, the last with about 10 spiral cords of tiny, prickly beads. Suture deeply channeled. Umbilicus very narrow and deep. Moderately common from 18 to 85 fathoms.