Page:American Seashells (1954).djvu/129

Rh Middle of whorl with a strong, sharp, smooth or beaded, spiral thread. Base of shell smoothish except for one smooth spiral thread near the periphery and one heavily beaded cord bordering the deep, round umbilicus. Entire shell with numerous microsc0pic incised lines. Very commonly dredged from 35 to 150 fathoms, but also recorded from 683 fathoms.

$1/2$ to $3/4$ inch in length, equally wide, solid, semi-gloss. Aperture circular. Umbilicus fairly wide, round, very deep. Whorls 7, shouldered just below the suture by a flat shelf. Lower $2/3$ of whorl with numerous weak spiral cords that are smoothish in the last whorl but crossed by numerous axial riblets in the early whorls. Color tan with light-mauve stains and mottlings. Interior iridescent. Moderately common from 20 to 339 fathoms.

$1/4$ inch in diameter, spire flat, surface smooth except for a spiral row of low pimples just below the suture. Whorls about 5. Umbilicus fairly wide, very deep, its squarish edge bearing numerous, neat, rounded creases. Columella straight. Color whitish gray with a beautiful opalescent sheen, especially inside the aperture. Top of whorls colored with chestnut, zebra-like axial stripes. Very commonly brought up in dredging hauls off Miami from 50 to 100 fathoms. The form inornata Dall lacks the pimples just below the suture.