In form and texture greatly resembling the Argonauta, but distinguished
by only having one keel on the whole length of the back.
Shell symmetrical, carinated or not, very thin, slightly compressed,
without spire, but with the summit slightly recurved posteriorly;
aperture oval and very entire.
Carinaria vitrea.
C. fragilis.
C. cymbium.
_C. vitrea._ The glassy Carinaria.
Species very rare and beautiful, thin, papyraceous, very fragile and
semitransparent; a serrated keel rises up its front, and the sides are
decorated with ribs parallel to the base.
_C. fragilis._ The fragile Carinaria.
Species smaller, very thin, striated longitudinally, diverging from the
summit to the margin; no keel.
_C. cymbium._ The minute Carinaria.
Species not larger than a grain of sand.
GLOSSARY
OF TERMS USED IN CONCHOLOGY.