230
MARINE MOLLUSCS AS HOSTS BOR SYMBIOSES
Later, Qiard (1897a) described the same cercaria as C. lutea. It has also
been referred to as C . pectinata by Huet (1891), Pelseneer (1896, 1906),
Fujita (1906, 1907), Kobayashi (1922), Dollfus (1911, 1925) and Palombi
(1932, 1933, 1934a). Palombi (1934b) finally was able to associate this
cercaria with the adult in the intestine of Atherina spp.
The sporocysts of B. bacciger are found in the visceral mass and
reproductive organs of Tapes decussatus (= Amygdala decussata),
Tapes pullastra, T . semidecussata, T. aureus, Donax vittatus, Pholas
candida and Tellina exigua. It has been found in the Mediterranean,
the Adriatic and the Atlantic in European waters, and in Japanese
waters.
Description of stages in mollusc. Sporocyst (Fig. 139) simple,
elongate, and sacculate, 0.5-3.0 mm long, 0.18-0-28 mm in diameter,
enclosing numerous cercariae at approximately the same stage of
development (synchronized development). Cercaria (Fig. 140) trichocercous, i.e. with setiferous tail; body ovoid, 0.22 mm long, 0-lOmm
wide ; anterior sucker 0.041 mm in diameter ; ventral sucker at or near
middle of body, 0.040 mm in diameter; no prepharynx; pharynx
0.021 mm in diameter ; esophagus fairly long ; intestinal caeca terminating immediately below level of ventral sucker ; two cephalic (penetration) glands on each side of esophagus, emptying to exterior anteriorly
each by its own duct ; two testes (non-functional), one on each side at
postero-lateral margin of ventral sucker ; small ovarial anlage situated
between testes ; excretory vesicle Y-shaped, with arms reaching level of
caecal bifurcation; tail, 0.47 mm long, 0.034 mm wide, with lateral
setae along entire length; each seta measures 0.12-0.20 mm long.
According to Palombi (1934b), the cercariae, after
escaping from the pelecypod first intermediate host, penetrate and
encyst as metacercariae in Erichthonius difformis, which, when eaten
by Atherina spp., develop into adults in the alimentary tract.
Sporocysts in the first intermediate host are
known to cause parasitic castration.
Life cycle.
Other information.
21. Proctoeces maculatus Looss, 1901. (Fig. 141)
(Superorder Anepitheliocystidia; order Strigeatoidea; suborder Azygiata;
Uzmann (1953) described a microcercous cercaria, Cercaria milfordensis, which develops in sporocysts found in the blood vessels and
sinuses of Mytilus edulis collected from Mill Neck, Long Island, New
York, and Milford and Bridgeport, Connecticut. It was reported to be
absent from the Massachusetts coast ; however, Stunkard and Uzmann
superfamily Fellodistomatoidea; family Fellodistomatidae)
MARINE MOLLUSCS AS HOSTS BOR SYMBIOSES
Later, Qiard (1897a) described the same cercaria as C. lutea. It has also
been referred to as C . pectinata by Huet (1891), Pelseneer (1896, 1906),
Fujita (1906, 1907), Kobayashi (1922), Dollfus (1911, 1925) and Palombi
(1932, 1933, 1934a). Palombi (1934b) finally was able to associate this
cercaria with the adult in the intestine of Atherina spp.
The sporocysts of B. bacciger are found in the visceral mass and
reproductive organs of Tapes decussatus (= Amygdala decussata),
Tapes pullastra, T . semidecussata, T. aureus, Donax vittatus, Pholas
candida and Tellina exigua. It has been found in the Mediterranean,
the Adriatic and the Atlantic in European waters, and in Japanese
waters.
Description of stages in mollusc. Sporocyst (Fig. 139) simple,
elongate, and sacculate, 0.5-3.0 mm long, 0.18-0-28 mm in diameter,
enclosing numerous cercariae at approximately the same stage of
development (synchronized development). Cercaria (Fig. 140) trichocercous, i.e. with setiferous tail; body ovoid, 0.22 mm long, 0-lOmm
wide ; anterior sucker 0.041 mm in diameter ; ventral sucker at or near
middle of body, 0.040 mm in diameter; no prepharynx; pharynx
0.021 mm in diameter ; esophagus fairly long ; intestinal caeca terminating immediately below level of ventral sucker ; two cephalic (penetration) glands on each side of esophagus, emptying to exterior anteriorly
each by its own duct ; two testes (non-functional), one on each side at
postero-lateral margin of ventral sucker ; small ovarial anlage situated
between testes ; excretory vesicle Y-shaped, with arms reaching level of
caecal bifurcation; tail, 0.47 mm long, 0.034 mm wide, with lateral
setae along entire length; each seta measures 0.12-0.20 mm long.
According to Palombi (1934b), the cercariae, after
escaping from the pelecypod first intermediate host, penetrate and
encyst as metacercariae in Erichthonius difformis, which, when eaten
by Atherina spp., develop into adults in the alimentary tract.
Sporocysts in the first intermediate host are
known to cause parasitic castration.
Life cycle.
Other information.
21. Proctoeces maculatus Looss, 1901. (Fig. 141)
(Superorder Anepitheliocystidia; order Strigeatoidea; suborder Azygiata;
Uzmann (1953) described a microcercous cercaria, Cercaria milfordensis, which develops in sporocysts found in the blood vessels and
sinuses of Mytilus edulis collected from Mill Neck, Long Island, New
York, and Milford and Bridgeport, Connecticut. It was reported to be
absent from the Massachusetts coast ; however, Stunkard and Uzmann
superfamily Fellodistomatoidea; family Fellodistomatidae)