364
N. BALAKRISHNAN NAIR AND M. SARASWATHY
teredo norvagica (Yonge, 1927), Teredo utriculus (Roch, 1940), T .
( Teredothyra) dominicensis and T . sigerfoosi (Nototeredo knoxi) (Clapp,
1951). In certain species with flattened pallets, e.g. Teredora and
Nototeredo, calcareous transverse septa occur in the attenuated tips of
the tubes. The pallets fit against these incomplete partitions, some
distance within the aperture while closing the burrow (Dons, 1946).
In some species like Teredothyra dominicensis (Bartsch) the posterior
a
b
d
e
f
C
FIG. 12. The distal ends of the siphons of shipworms : (a) inhalant siphon (slit open) of
Teredo navalia; (b) exhalant siphon of Teredo utriculus; (c) inhalant siphon of
Bankia minima; (d-g) sections passing through the inhalant siphons of: (d) T .
navalis; (e) T . pedicellata; (f) T . utricuZus; (g) Bankia minima. (After Rooh, 1940) ;
(h) posterior end of Nausitma fusticula showing the elaborate incurrent siphon ;
(i) enlargement of a single " tentacle " showing the structure of the inner surface.
(After Turner, 1966.)