472
N. BALAKRISHNAN NAIR AND M. SARASWATHY
Edmondson (1942, 1945, 1946b) also reported the incidence of this
species at Hawaii especially in the burrows of Teredo milleri. Moll
(1939) observed “ cocoons ” of a turbellarian identified as Stylochoplana
sp. in inhabited burrows and considers that it is more probably a
scavenger.
Rancurel (1954b) has reported the occurrence of an acanthocephalan
in the ovarian mass and cysts of trematodes infesting the exhalant
siphons of Teredo petiti Recluz collected from the west coast of Africa.
Of the many natural enemies of shipworms few have attracted
greater attention than the polychaetes. These are usually found in close
association with submerged timber and more often within the empty
burrows of shipworms. There is no agreement about the role these
worms play in the ecology of shipworms. Are they carnivores, or just
casual associates or scavengers? Two species, Nereilepas fucata and
Lycastis senegalensis, more especially the former have been repeatedly
mentioned as close associates of shipworms. Authors like Rathke
(1799), Vrolik et al. (1860a)) Clavenad (1879), Calderon (1893)) Herpin
(1935) believe that the worm is a natural enemy of shipworms and Hedley (1901) even suggested the introduction of the European species of
Nereis to check the ravages of shipworms in Australia. Others, however,
do not share these views, although agreeing that the polychaetes do, a t
times, invade the burrows and devour the shipworms (see Calman,
1919 ; Redgrave, 1920 ; Clapp, 1935a ; Roch, 1940). Another view is that
these wormsnever prey on shipworms (McIntosh 1908 ; Cormio, 1947).
Potamopyrgus ciliatus (Gould) a small prosobranch gastropod, has
been recorded from the Congo estuary living in the burrows inhabited
by shipworms (Bequaert and Clench, 1941). The exact nature of this
association has not been elucidated.
Among the copepod crustaceans, numerous species have been reported as “parasites” or as commensals of molluscs (Monod and
Dollfus, 1932). Those of commercially important species of molluscs
have been recently reviewed by Cheng (1967). At least 2 species of
copepods have so far been reported from shipworms : (1) Teredicola
typica Wilson inhabiting the infra-branchial cavity of Teredo and
Bankia of Hawaii (Wilson, 1942; Edmondson, 1945, 1946, 1946b).
Nearly 75% of Teredo milleri collected from Hawaii has been found
infested with the parasite. Growth of infested shipworms appears
retarded but otherwise they are little affected; (2) Teredophilus
renicola Rancurel occurring in the renal canals of Teredo petiti from the
west coast of Africa (Rancurel, 1954). An interesting feature is that
only females of this copepod were found within the body of the host.
Other crustaceans reported in association with shipworms are an
N. BALAKRISHNAN NAIR AND M. SARASWATHY
Edmondson (1942, 1945, 1946b) also reported the incidence of this
species at Hawaii especially in the burrows of Teredo milleri. Moll
(1939) observed “ cocoons ” of a turbellarian identified as Stylochoplana
sp. in inhabited burrows and considers that it is more probably a
scavenger.
Rancurel (1954b) has reported the occurrence of an acanthocephalan
in the ovarian mass and cysts of trematodes infesting the exhalant
siphons of Teredo petiti Recluz collected from the west coast of Africa.
Of the many natural enemies of shipworms few have attracted
greater attention than the polychaetes. These are usually found in close
association with submerged timber and more often within the empty
burrows of shipworms. There is no agreement about the role these
worms play in the ecology of shipworms. Are they carnivores, or just
casual associates or scavengers? Two species, Nereilepas fucata and
Lycastis senegalensis, more especially the former have been repeatedly
mentioned as close associates of shipworms. Authors like Rathke
(1799), Vrolik et al. (1860a)) Clavenad (1879), Calderon (1893)) Herpin
(1935) believe that the worm is a natural enemy of shipworms and Hedley (1901) even suggested the introduction of the European species of
Nereis to check the ravages of shipworms in Australia. Others, however,
do not share these views, although agreeing that the polychaetes do, a t
times, invade the burrows and devour the shipworms (see Calman,
1919 ; Redgrave, 1920 ; Clapp, 1935a ; Roch, 1940). Another view is that
these wormsnever prey on shipworms (McIntosh 1908 ; Cormio, 1947).
Potamopyrgus ciliatus (Gould) a small prosobranch gastropod, has
been recorded from the Congo estuary living in the burrows inhabited
by shipworms (Bequaert and Clench, 1941). The exact nature of this
association has not been elucidated.
Among the copepod crustaceans, numerous species have been reported as “parasites” or as commensals of molluscs (Monod and
Dollfus, 1932). Those of commercially important species of molluscs
have been recently reviewed by Cheng (1967). At least 2 species of
copepods have so far been reported from shipworms : (1) Teredicola
typica Wilson inhabiting the infra-branchial cavity of Teredo and
Bankia of Hawaii (Wilson, 1942; Edmondson, 1945, 1946, 1946b).
Nearly 75% of Teredo milleri collected from Hawaii has been found
infested with the parasite. Growth of infested shipworms appears
retarded but otherwise they are little affected; (2) Teredophilus
renicola Rancurel occurring in the renal canals of Teredo petiti from the
west coast of Africa (Rancurel, 1954). An interesting feature is that
only females of this copepod were found within the body of the host.
Other crustaceans reported in association with shipworms are an