THE BIOLOGY O F WOOD-BORING TEREDINID MOLLUSCS
425
Lyrodus bipartita (Jeffreys) from the Gulf of Panama in 3 710 m and
Teredothyra smithi (Bartsch) from 5 050 m in the Sulu Sea. These
records are from the wood dredged by the Danish research vessel
“ Galathea ”. The Atlantique Sud Expedition had also collected
Bankia carinata from different depths, in 250 m near Port Gentil,
Congo, in 200 m about 40 miles WSW of Mouta Secca Point, Congo, and
in 145 m about 35 miles west of Ambrizette, Congo. Nototeredo norwqica had been dredged from 944m by HMS “Triton” off the
north coast of Scotland. Bankia carinata, Teredothyra atwoodi and T .
docotana have also been collected from test boards about 2 miles east
of Fort Lauderdale, Florida in depths o f 100 m (Turner, 1966).
Our information about teredinids from deep water is thus very
limited and fragmentary. It will be seen that many of the species that
occur in deep water also occur in shallow waters. These findings, however, suggest that teredinids are able to settle, grow and reproduce at
considerable depths.
XIII. GROWTH RATES
Studies on growth rates are important because they are directly
related to the damage done to timber. Each shipworm destroys a
column of wood of the same dimension as its largest size. The use of
X-ray photography (Ralph and Hurley, 1952) and the utilization of
sterioradiography (Crisp et al., 1953) have facilitated the study of
growth rates of their calcium-lined burrows without damaging the substrate or disturbing the animals. Comparisons of growth rates of
different species o f shipworms recorded from different kinds of timber
from different localities do not seem to have much meaning. The
growth rates of different species occurring in widely separated places
are likely to be different and even in the consideration of growth rates of
the same species, unless the latitude, substrate involved etc. are the
same the values are likely to vary. Growth rates need not be identical
even when latitude, species and substrate are all the same during
the different seasons since they are likely to be influenced by the
prevailing hydrographic conditions. Further, Scheltema and Truitt
(1954) observed that Bankia gouldi has different rates of growth at
different localities of the same estuary during the same time depending on the number of individuals which have settled. Despite these
factors, a brief review of the results of growth rate studies appears
justified.
In Bankia setacea an average rate of boring of about 4.7 cm/month
was noted by Kofoid et al. (1927) ; at Friday Harbour, Johnson and
Miller (1935) observed that the largest specimen of B. setacea measured
425
Lyrodus bipartita (Jeffreys) from the Gulf of Panama in 3 710 m and
Teredothyra smithi (Bartsch) from 5 050 m in the Sulu Sea. These
records are from the wood dredged by the Danish research vessel
“ Galathea ”. The Atlantique Sud Expedition had also collected
Bankia carinata from different depths, in 250 m near Port Gentil,
Congo, in 200 m about 40 miles WSW of Mouta Secca Point, Congo, and
in 145 m about 35 miles west of Ambrizette, Congo. Nototeredo norwqica had been dredged from 944m by HMS “Triton” off the
north coast of Scotland. Bankia carinata, Teredothyra atwoodi and T .
docotana have also been collected from test boards about 2 miles east
of Fort Lauderdale, Florida in depths o f 100 m (Turner, 1966).
Our information about teredinids from deep water is thus very
limited and fragmentary. It will be seen that many of the species that
occur in deep water also occur in shallow waters. These findings, however, suggest that teredinids are able to settle, grow and reproduce at
considerable depths.
XIII. GROWTH RATES
Studies on growth rates are important because they are directly
related to the damage done to timber. Each shipworm destroys a
column of wood of the same dimension as its largest size. The use of
X-ray photography (Ralph and Hurley, 1952) and the utilization of
sterioradiography (Crisp et al., 1953) have facilitated the study of
growth rates of their calcium-lined burrows without damaging the substrate or disturbing the animals. Comparisons of growth rates of
different species o f shipworms recorded from different kinds of timber
from different localities do not seem to have much meaning. The
growth rates of different species occurring in widely separated places
are likely to be different and even in the consideration of growth rates of
the same species, unless the latitude, substrate involved etc. are the
same the values are likely to vary. Growth rates need not be identical
even when latitude, species and substrate are all the same during
the different seasons since they are likely to be influenced by the
prevailing hydrographic conditions. Further, Scheltema and Truitt
(1954) observed that Bankia gouldi has different rates of growth at
different localities of the same estuary during the same time depending on the number of individuals which have settled. Despite these
factors, a brief review of the results of growth rate studies appears
justified.
In Bankia setacea an average rate of boring of about 4.7 cm/month
was noted by Kofoid et al. (1927) ; at Friday Harbour, Johnson and
Miller (1935) observed that the largest specimen of B. setacea measured