THE BIOLOGY OF WOOD-BORING TEREDINID MOLLUSCS
469
economically and potentially important parasites of oysters, clams and
mussels (see Cheng, 1967). It is indeed very strange that, despite their
great economic importance, no detailed study has been made of the
parasites and associates of wood-boring organisms.
Several organisms are associated with shipworms in their natural
habitat but so far no cause-and-effect relationship has been established.
There is always the possibility that certain parasites and predators may
be utilized as effective agents of biological control.
Protozoa parasitic in marine molluscs of commercial importance
have, however, recently been reviewed by Cheng (1967). All known
protozoan parasites of shipworms belong to the ciliata. In 1887 Durand
noticed the occurrence of several protozoan parasites in Teredo navalis
but did not name them. Nelson (1923) described a heterotrichous
ciliate Boveria teredinidi infesting the gill lamellae of Teredo navalis and
Bankia gouldi in Barnegat Bay, New Jersey and observed (Nelson, 1925)
that the parasite does no apparent harm to its host. This species has
subsequently been reported from San Francisco Bay (Pickard, 1927)
also without apparent pathogenic effects. According to Pickard this
ciliate does not invade the tissues of its host. Nevertheless, developmental stages of certain parasitic protozoans, probably those of
Boveria have been described by Ikeda and Ozaki (1918) in the mantle
tissue of Teredo. Levinson (1941) has described a new species B.
zenkevitchi from the branchial cavity of T . navalis in the Bay of Sevastopol, the infestation in this instance is reported as taking place as the
shipworm penetrates the wood.
The holotrich Architophryu sp. has also been reported as parasitic
on shipworms (Grave, 1928 ; Roch, 1940).
Recent studies by Santhakumari in our laboratory have brought to
light an interesting fauna of protozoan associates from shipworms (see
Nair, 1968). So far we have collected species belonging to Boveridae,
Urceolaridae, Thigmophryidae, Spirostomidae, Licnophoridae, Hysterocinetidae, Stentoridae, and also Zoothamnium, Lagenophrys and
Tvochilioides. Detailed taxonomical and ecological studies on these
protozoans are in progress.
Association between hydroids of the genus Eugymnanthea (Fig. 56)
and bivalves has been reported from time to time (Palombi, 1935;
Cerruti, 1941; Mattox and Crowell, 1951; Yamada, 1950; Crowell,
1956). The first record of this interesting association between a hydroid
recognizable as belonging to Eugymnanthea and shipworms has been by
Santhakumari and Nair (1969) who reported its occurrence in Nausitora
hedleyi and Teredo furcifera from Cochin backwaters, south-west coast
of India. This hydroid, however, differs from all previously describcd
469
economically and potentially important parasites of oysters, clams and
mussels (see Cheng, 1967). It is indeed very strange that, despite their
great economic importance, no detailed study has been made of the
parasites and associates of wood-boring organisms.
Several organisms are associated with shipworms in their natural
habitat but so far no cause-and-effect relationship has been established.
There is always the possibility that certain parasites and predators may
be utilized as effective agents of biological control.
Protozoa parasitic in marine molluscs of commercial importance
have, however, recently been reviewed by Cheng (1967). All known
protozoan parasites of shipworms belong to the ciliata. In 1887 Durand
noticed the occurrence of several protozoan parasites in Teredo navalis
but did not name them. Nelson (1923) described a heterotrichous
ciliate Boveria teredinidi infesting the gill lamellae of Teredo navalis and
Bankia gouldi in Barnegat Bay, New Jersey and observed (Nelson, 1925)
that the parasite does no apparent harm to its host. This species has
subsequently been reported from San Francisco Bay (Pickard, 1927)
also without apparent pathogenic effects. According to Pickard this
ciliate does not invade the tissues of its host. Nevertheless, developmental stages of certain parasitic protozoans, probably those of
Boveria have been described by Ikeda and Ozaki (1918) in the mantle
tissue of Teredo. Levinson (1941) has described a new species B.
zenkevitchi from the branchial cavity of T . navalis in the Bay of Sevastopol, the infestation in this instance is reported as taking place as the
shipworm penetrates the wood.
The holotrich Architophryu sp. has also been reported as parasitic
on shipworms (Grave, 1928 ; Roch, 1940).
Recent studies by Santhakumari in our laboratory have brought to
light an interesting fauna of protozoan associates from shipworms (see
Nair, 1968). So far we have collected species belonging to Boveridae,
Urceolaridae, Thigmophryidae, Spirostomidae, Licnophoridae, Hysterocinetidae, Stentoridae, and also Zoothamnium, Lagenophrys and
Tvochilioides. Detailed taxonomical and ecological studies on these
protozoans are in progress.
Association between hydroids of the genus Eugymnanthea (Fig. 56)
and bivalves has been reported from time to time (Palombi, 1935;
Cerruti, 1941; Mattox and Crowell, 1951; Yamada, 1950; Crowell,
1956). The first record of this interesting association between a hydroid
recognizable as belonging to Eugymnanthea and shipworms has been by
Santhakumari and Nair (1969) who reported its occurrence in Nausitora
hedleyi and Teredo furcifera from Cochin backwaters, south-west coast
of India. This hydroid, however, differs from all previously describcd