6. THE PHYLA PORIFERA, CNIDARIA AND PLATYHELMINTHES
201
described as Imogine oculifera by Girard (1853), it has since been transferred to the genus Stylochus as S. oculiferus by Diesing (1861).
According to Hyman (1940b)) Pearse’s S. Jloridanus is a synonym. S.
oculiferus has been found along the coasts of Florida and North
Carolina. A good description has been given by Hyman (1940b).
4. Pseudostylochus ostreophagus Hyman, 1955
(Order Polycladida; suborder Acotylea; family Calliophanidae)
During 1953, shellfish biologists in the State of Washington suspected
that a polyclad turbellarian imported from Japan was responsible for
the destruction of the spat and young adults of Ostrea lurida. Specimens
of this polyclad were sent to Dr. L. H. Hyman who later (Hyman, 1955)
described it as representing a new species, Pseudostylochus ostreophagus.
That this turbellarian was imported from Japan was confirmed when
Mr. C. E. Woelke visited three localities in Japan, the Liyagi Prefecture,
the village of Oginshama on the Osika Peninsula, and the village of
Sabusawa in the Urato Islands, and found the identical worm.
The relationship of P. ostreophagus to Ostrea lurida in addition to
Crassostrea gigas and C. virginica was studied by Woelke (1957). He
reported that destruction of the oysters is accomplished when the
turbellarian penetrates the shell and inserts the edge of its pharyngeal
folds by the use of which it severs the adductor muscle from the right
valve. Then the worm crawls between the gaping valves and ingests
the entire living oyster. Thus, P. ostreophagus must be considered a
predator rather than a parasite.
The actual method of shell penetration by P. ostreophagus is not
well understood, although it is believed to be a chemical process since
Woelke has observed the presence of ( ( gelatinous mucoid droplets on
the incomplete shell perforations of attacking worms.” Unpublished
experiments by Smith ( 1955), however, have indicated that homogenates
of whole worms will not dissolve oyster shells.
RADCLi FFe
(Order. Polycladida; suborder Acotylea; faniily Hoploplanidae)
5. Hoploplana inquilina Wheeler, 1894
This turbellarian, originally described by Wheeler (1 894) as Planocera
inquilina, has been referred to the genus Hoploplana by Bock (1913).
It has since been studied by Hyman (1939, 1940b). It is being briefly
mentioned here since this sluggishly creeping worm is said to be a
commensal in the mantle cavity of Busycon.
201
described as Imogine oculifera by Girard (1853), it has since been transferred to the genus Stylochus as S. oculiferus by Diesing (1861).
According to Hyman (1940b)) Pearse’s S. Jloridanus is a synonym. S.
oculiferus has been found along the coasts of Florida and North
Carolina. A good description has been given by Hyman (1940b).
4. Pseudostylochus ostreophagus Hyman, 1955
(Order Polycladida; suborder Acotylea; family Calliophanidae)
During 1953, shellfish biologists in the State of Washington suspected
that a polyclad turbellarian imported from Japan was responsible for
the destruction of the spat and young adults of Ostrea lurida. Specimens
of this polyclad were sent to Dr. L. H. Hyman who later (Hyman, 1955)
described it as representing a new species, Pseudostylochus ostreophagus.
That this turbellarian was imported from Japan was confirmed when
Mr. C. E. Woelke visited three localities in Japan, the Liyagi Prefecture,
the village of Oginshama on the Osika Peninsula, and the village of
Sabusawa in the Urato Islands, and found the identical worm.
The relationship of P. ostreophagus to Ostrea lurida in addition to
Crassostrea gigas and C. virginica was studied by Woelke (1957). He
reported that destruction of the oysters is accomplished when the
turbellarian penetrates the shell and inserts the edge of its pharyngeal
folds by the use of which it severs the adductor muscle from the right
valve. Then the worm crawls between the gaping valves and ingests
the entire living oyster. Thus, P. ostreophagus must be considered a
predator rather than a parasite.
The actual method of shell penetration by P. ostreophagus is not
well understood, although it is believed to be a chemical process since
Woelke has observed the presence of ( ( gelatinous mucoid droplets on
the incomplete shell perforations of attacking worms.” Unpublished
experiments by Smith ( 1955), however, have indicated that homogenates
of whole worms will not dissolve oyster shells.
RADCLi FFe
(Order. Polycladida; suborder Acotylea; faniily Hoploplanidae)
5. Hoploplana inquilina Wheeler, 1894
This turbellarian, originally described by Wheeler (1 894) as Planocera
inquilina, has been referred to the genus Hoploplana by Bock (1913).
It has since been studied by Hyman (1939, 1940b). It is being briefly
mentioned here since this sluggishly creeping worm is said to be a
commensal in the mantle cavity of Busycon.