4. ANALYSIS O F FACTORS INVOLVED I N SYMBIOSIS
101
reported that in 1926 oysters from Matagorda Bay, Texas, were
extremely heavily infested with Diplothyra smithii, with one adult
harboring over 200 clams. Relative to this relationship, it is of interest
to note that as the cavity bored by the clam increased and approached
the nacrous layer, the oyster reacted by depositing layers of conchiolin
over the nearly perforated areas (nacrezation). Thus, rarely does one
find boring clams in contact with the mantle.
Another example of commensals which live in the mantle cavities of
marine pelecypods are hydroids of the genus Eugymnanthea. As in
practically all relationships categorized as commensalism, the exact
nature of the relationships between the above mentioned hydroids and
their hosts remain unexamined.
Another large group of arthropods which have been found within
the mantle cavities or elsewhere on the surface of the soft tissues of
marine molluscs is the copepods. Again, little is known about the
relationships of these with their hosts although the individuals who
have studied these most extensively, Wilson (1921, 1935), Yamaguti
(1936), Humes (1953, 1954a, 195813) and Humes and Cressey (1958,
1960) have considered them to be parasites. On the other hand,
Bocquet and Stock (1957), who have also studied them extensively,
referred to these copepods as commensals.
Among the pelecypods, which according to Humes (1958a) are
associated with more copepods than any other molluscan class, representatives of the copepod genera Modiolicola, Tisbe, Ostrincola,
Pseudomyicola, Conchyliurus, Myocheres, Paranthessius, Myicola, and
others are found living in their mantle cavities where they cling to the
surfaces of gills. These ectosymbionts, unlike endoparasitic copepods,
are relatively unmodified in form. Little is known about the pathology,
if any, caused by these copepods.
Among the gastropods, the prosobranchs are hosts for a few genera
of copepods, including Trochicola, Ceratocheres, Panaietis and Monstrilla. The opisthobranchs, on the other hand, are hosts to many
genera among which the most common are Lichomolgus, Splanchnotrophus, Briarella, Artotrogus and Anthessius. Some, like Lichomolgus,
are found on the surfaces of the gills or mantle. Others are endosymbiotic, probably parasitic, Again, the surface-dwelling species are
little or not modified, while the endosymbiotic forms are generally
greatly modified. Nothing is known about pathological changes
Among the cephalopods, only a few copepods have been reported.
Most of t,hese are ectoparasites. For example, Cholidya occurs on the
arm membranes of Benthooctopus, Anchicaligus lives in the mantle
associated with these copepods.
RAOCL IFCP
101
reported that in 1926 oysters from Matagorda Bay, Texas, were
extremely heavily infested with Diplothyra smithii, with one adult
harboring over 200 clams. Relative to this relationship, it is of interest
to note that as the cavity bored by the clam increased and approached
the nacrous layer, the oyster reacted by depositing layers of conchiolin
over the nearly perforated areas (nacrezation). Thus, rarely does one
find boring clams in contact with the mantle.
Another example of commensals which live in the mantle cavities of
marine pelecypods are hydroids of the genus Eugymnanthea. As in
practically all relationships categorized as commensalism, the exact
nature of the relationships between the above mentioned hydroids and
their hosts remain unexamined.
Another large group of arthropods which have been found within
the mantle cavities or elsewhere on the surface of the soft tissues of
marine molluscs is the copepods. Again, little is known about the
relationships of these with their hosts although the individuals who
have studied these most extensively, Wilson (1921, 1935), Yamaguti
(1936), Humes (1953, 1954a, 195813) and Humes and Cressey (1958,
1960) have considered them to be parasites. On the other hand,
Bocquet and Stock (1957), who have also studied them extensively,
referred to these copepods as commensals.
Among the pelecypods, which according to Humes (1958a) are
associated with more copepods than any other molluscan class, representatives of the copepod genera Modiolicola, Tisbe, Ostrincola,
Pseudomyicola, Conchyliurus, Myocheres, Paranthessius, Myicola, and
others are found living in their mantle cavities where they cling to the
surfaces of gills. These ectosymbionts, unlike endoparasitic copepods,
are relatively unmodified in form. Little is known about the pathology,
if any, caused by these copepods.
Among the gastropods, the prosobranchs are hosts for a few genera
of copepods, including Trochicola, Ceratocheres, Panaietis and Monstrilla. The opisthobranchs, on the other hand, are hosts to many
genera among which the most common are Lichomolgus, Splanchnotrophus, Briarella, Artotrogus and Anthessius. Some, like Lichomolgus,
are found on the surfaces of the gills or mantle. Others are endosymbiotic, probably parasitic, Again, the surface-dwelling species are
little or not modified, while the endosymbiotic forms are generally
greatly modified. Nothing is known about pathological changes
Among the cephalopods, only a few copepods have been reported.
Most of t,hese are ectoparasites. For example, Cholidya occurs on the
arm membranes of Benthooctopus, Anchicaligus lives in the mantle
associated with these copepods.
RAOCL IFCP