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TROCHIDAE 111
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 microscopic incised lines. Very commonly dredged from 35
to 150 fathoms, but also recorded from 683 fathoms.
Solariella peramabilis Carpenter Lovely Pacific Solarelle
Alaska to San Diego, California.
Figure 31b
^ to % 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 % of whorl with numerous weak spiral
cords that are smoothish in the last whorl but crossed by numerous axial rib-
lets in the early whorls. Color tan with light-mauve stains and mottlings.
Interior iridescent. Moderately common from 20 to 339 fathoms.
Figure 32. a, Gaza ivatsoni Dall (nat. size); b and c, Solariella lacunella Dall
X4; d and e, Microgaza rotella Dall X4. All from the Atlantic.
Genus Microgaza Dall 1881
Microgaza rotella Dall Dall's Dwarf Gaza
North Carolina to south Florida and the West Indies.
Figure 32d, e
% 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. Colu-
mella straight. Color whitish gray with a beautiful opalescent sheen, espe-
cially inside the aperture. Top of whorls colored with chestnut, zebra-like
axial stripes. Very commonly brought up in dredging hauls off A4iami from
50 to 100 fathoms. The form i?iornata Dall lacks the pimples just below the
suture.