Biology of
Aspatharia sinuata
Delivered by
SHITTU Olalere
Dept. of Zoology,
University of Ilorin, Nigeria
External Shell Characteristics
Internal Shell Characteristics
Internal Shell Characteristics
Internal Shell Characteristics
The Mantle Cavity
 The posterior edges of the mantle folds are modified
to form dorsal excurrent and ventral incurrent
openings.
Gills
 The mantle and gills of
bivalves are involved in
gaseous exchange.
 The gills are modified for
filter feeding, they originated
from the primitive ctenidia by
elongation of the filaments on
both sides of the central axis.
 The end of the filaments folds
backward to make the
ctenidia filament assume a
slender W shape.
Section through heart and Gills
Feeding
 Feeding mechanism
Anatomy of the Internal Organs of Bivalves
Anatomy of the Heart
Reproduction and Development
 The glochidia larvae
seeks, attach to fins and
gills of fishes where they
encyst.
 Fishes serve as agent of
dispersal.
 Encysted glochidia larvae
undergo metamorphosis
into adults which escape
from the cyst and sink to
the bottom of muds.
Life Cycle of Bivalves
 Marine forms
exhibits
external
fertilization
 Veliger larva
swims
for
about
two
weeks before
spat
formation.
 Four years to
reach
adulthood.
End of presentation
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