This genus was taken from the Venus, and is easily defined as distinct
from it by having four primary teeth on one valve, and only three united
on the other, with an isolated cavity, oval and parallel to the margin;
the lateral teeth divergent to the summit. In some species the internal
margin is entire, having the anterior cardinal tooth with a striated
canal or uneven sides; in others the anterior cardinal tooth is entire,
without a striated canal; sometimes the internal margin is crenulated or
dentated.
Shell solid, regular, equivalve, inequilateral; apices equal, recurved,
and slightly projecting; four primary teeth on one valve, of which three
are divergent and approximating at the base, and one remote; three
primary divergent teeth on the other valve, with a distant cavity
parallel to the edge.
Cytherea lusoria.
C. petechialis.
C. impudica.
C. castanea.
C. zonaria.
C. graphica.
C. morphina.
C. purpurata.
C. casta.
C. corbicula.
C. meretrix.
C. gigantea.
C. erycina.
C. lilacina.
C. impar.
C. erycinella.
C. pectoralis.
C. planatella.
C. florida.
C. nitidula.
C. Chione.
C. maculata.
C. citrina.
C. albina.
C. lata.
C. mactroides.
C. trigonella.
C. sulcatina.
C. Hebræa.
C. castrensis.
C. ornata.
C. picta.
C. tigrina.
C. scripta.
C. numulina.
C. muscaria.
C. pectinata.
C. gibbia.
C. ranella.
C. testudinalis.
C. divaricata.
C. cuneata.
C. placunella.
C. rugifera.
C. tripla.
C. Venetiana.
C. juvenilis.
C. rufa.
C. Guiniensis.
C. Dione.
C. Arabica.
C. trimaculata.
C. immaculata.
C. pellucida.
C. hepatica.
C. lucinalis.
C. lactea.
C. exoleta.
C. lincta.
C. concentrica.
C. prostrata.
C. interrupta.
C. tigerina.
C. punctata.
C. umbonella.
C. undatina.
C. pulicaris.
C. mixta.
C. abbreviata.
C. plicatina.
C. flexuosa.
C. macrodon.
C. lunularis.
C. squamosa.
C. lunaris.
C. cardilla.
C. cygnus.
C. dentaria.
_C. Chione._ The Chione Cytherea.
Thick, solid, heart-shaped, covered with a smooth brown epidermis,
beneath which the shell is of a beautiful purple; radiated
longitudinally, faintly wrinkled transversely, anterior cardinal tooth
entire, and without a striated canal; apex turned sideways, with a
cordiform depression.
_C. mactroides._ The Mactra-like Cytherea. Pl. 9, fig. 4.
Species thin, convex, triangular; summits very marked; margins sharp;
anterior cardinal tooth entire.
_C. pectinata._ The pectinated Cytherea.
Species oval, thick, solid, more or less compressed, costated,
pectinated upon the edges.