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280 American Seashells
Family RETUSIDAE
Genus Retusa Brown 1827
Retusa obtusa Montagu Arctic Barrel-bubble
Arctic Seas to off North Carolina.
Figure 59a
3 mm. in length, fairly fragile, smooth, stubby and with the spire commonly
slightly sunk or only a little elevated. Columella smooth. A chink-
like umbilicus is present. Color translucent-white with yellowish brown stain-
ing. Common from shore to 90 fathoms. R. pertejiuis Mighels and R.
turrita Moller are this species.
Retusa sulcata Orbigny Sulcate Barrel-bubble
North Carolina to southeast Florida and the West Indies.
2 mm. in length. Characterized by its small size, fine axial threads,
white color, oblong shape, flat sides and deeply sunken spire. Moderately
common from 3 to 95 fathoms.
Retusa canaliculata Say Channeled Barrel-bubble
Nova Scotia to Florida, Texas and the West Indies.
Plate 26X
4 to 6 mm. in length, solid, oblong with its spire moderately elevated,
but almost invariably eroded. Glossy smooth, except for microscopic growth
lines. Outer lip thin, advanced above. Columella of a single, raised, strong
spiral ridge. Suture slightly channeled. Nucleus (when present) very small
and pimple-like. Color white to cream, commonly with dark, rust-brown
staining. Acteocina candei Orbigny is probably only a southern representa-
tive of this species. A common shallow-water species which was formerly
placed in the genus Acteocina.
Genus Pyrunculus Pilsbry 1894
Pyrunculus caelatus Bush Bush's Barrel-bubble
Plate 26W
North Carohna to southeast Florida.
3 mm. in length, pyriform in shape, rather thick and opaque-white.
Spire concealed within a very deep pit. Rather rare from 15 to 43 fathoms.
Genus Rhizorus Montfort iSio
{Volvula A. Adams, not Gistel)
Rhizorus oxytatus Bush Southern Spindle-bubble
North Carolina to southeast Florida and Cuba.