The siphons of the Mino River Corbicula (Fig. 2A)
are of ambarine-orange color with black spots and áreas. The
two siphons are internally surrounded by a black ring. Between
the two siphons, and from the exhalant one, there are
two well marked black lines. The siphons are surrounded by
tentacles, usually with pigmented bases. Those of the inhalant
siphon are longer and with black spots in the middle. There
is no rule in the disposition of the fused mantle folds papillae
down to the inhalant siphon. There are specimens with a
single row and others with the papillae in a random pattern
(Fig. 2A) and intermedíate situations may be observed.
The gonadal tissue occupies, in the reproductive
season, most of the visceral mass. Each gonad is formed by
greenish arborescent follicles branching through the stroma
of the visceral mass. The common branch leads to a single
gonopore, one on each side of the body just above the excretory
apernare in the latero-dorsal edge of the visceral mass
(Fig. 2B).
One specimen of Goian, captured in July 1990,
presented developing larvae in the inner demibranchs (Fig.
7). The larvae are bivalved and D-shaped.