This genus of shells is remarkable for having in the interior cavity a
transverse funnel or tongue-shaped testaceous appendage, from which
originated its common name.
Shell conic, base orbicular; summit vertical and imperforated; cavity
deep, having at its interior summit a tongue-like appendage. This
appendage is sometimes vertical and sometimes like a horseshoe, having
on it a muscular impression of variable form.
Calyptræa extinctorium.
C. lævigata.
C. equestris.
C. tectum-sinense.
_C. extinctorium._ The extinguisher Calyptræa.
Species in which the internal appendage is horn-shaped; colour brownish.
_C. equestris._ The equestrian Calyptræa. Pl. 32, fig. 4.
Species in which the internal appendage is like a horseshoe, open in
front.
_C. tectum-sinense._ The Chinese roof Calyptræa.
Shell formed of separate, transverse, irregular round laminæ of uniform
size, attached to each other by the summit on the exterior of each,
presenting the appearance of a number of small flat Patellæ piled one on
the other; colour yellowish, margin entire, very glossy within.