6. THE PHYLA PORIFERA, CNIDARIA AND PLATYHELMINTHES
21 1
chus) about 0.04 mm x 0.03 mm ; ventral sucker, 0.025 mm in diameter,
situated behind middle of body, 0.16-0.17 mm from anterior end;
intestinal caecum simple and sac-like ; body with few rows of minute
cuticular spines a t anterior end; stem of tail covered with minute
spines ; two testes well developed, spherical, one behind the other, just
posterior to ventral sucker ; vas deferens leads from testes to prominent
cirrus opening a t posterior tip of body ; no excretory vesicle seen.
Other information. From gross descriptions given by Cole (1935),
it would appear that the sporocysts of B. mytili, like those of other
known bucephalids, could cause parasitic castration in the molluscan
host.
5 . Cercaria noblei Giles, 1962. (Fig. 118)
(Superorder Anepitheliocystidia; order Strigeatoidea; suborder Azygiata;
This bucephalid cercaria was described by Giles (1962) from Mytilus
californianus collected a t Dillon Beach, Marin County, California.
Description of stages in mollusc. Sporocyst typically bucephalid,
orange in color, occupying principally the gonads, may occur in other
tissues, including kidney, packed with cercariae at various stages of
development. Cercaria (Fig. 118) with blunt cylindrical body, tapering
slightly a t posterior end, 0.155-0.230 mm (average 0.185 mm) long x
0.032-0.058 mm (average 0.040 mm) wide; tail stem of three lobes,
median lobe 0.066-0-073mm (average 0-070mm)long x 0~015-0~018mm
(average 0.017 mm) in diameter, lateral lobes 0.051 mm long x
0.016 mm in diameter ; long filamentous furcae highly contractile,
2-7.5 times length of body when extended, generally directly anteriorly ;
sucker-like structure a t free end of each lobe of tail stem; anterior
holdfast (referred to as a haptor by Giles) eversible and cup-shaped,
0.045 mm long, covered with small spines distally ; butterfly-shaped
cytogenous gland, 0.040 mm long x 0.035 mm wide, immediately
posterior to haptor; ventral oral sucker in posterior half of body,
0.014-0-016 mm in diameter ; intestinal caecum simple, sac-like,
0.031 mm long; two testes posterior to ventral sucker, right testis
0.018 mm x 0.010 mm, left testis 0.017 mm x 0.017 mm; cirrus pouch,
ventral to left testis, continuous with genital atrium on ventral body
surface immediately anterior to posterior body terminal ; ovary,
0.015 mm x 0.008 mm, dorsal to right testis and extends slightly
anterior to i t ; excretory vesicle extends from body-tail junction to
posterior edge of ventral sucker.
superfamily Bucephaloidea; family Bucephalidae)
Other injormation. Nothing else is knowB abmf C, n~bZ..i
21 1
chus) about 0.04 mm x 0.03 mm ; ventral sucker, 0.025 mm in diameter,
situated behind middle of body, 0.16-0.17 mm from anterior end;
intestinal caecum simple and sac-like ; body with few rows of minute
cuticular spines a t anterior end; stem of tail covered with minute
spines ; two testes well developed, spherical, one behind the other, just
posterior to ventral sucker ; vas deferens leads from testes to prominent
cirrus opening a t posterior tip of body ; no excretory vesicle seen.
Other information. From gross descriptions given by Cole (1935),
it would appear that the sporocysts of B. mytili, like those of other
known bucephalids, could cause parasitic castration in the molluscan
host.
5 . Cercaria noblei Giles, 1962. (Fig. 118)
(Superorder Anepitheliocystidia; order Strigeatoidea; suborder Azygiata;
This bucephalid cercaria was described by Giles (1962) from Mytilus
californianus collected a t Dillon Beach, Marin County, California.
Description of stages in mollusc. Sporocyst typically bucephalid,
orange in color, occupying principally the gonads, may occur in other
tissues, including kidney, packed with cercariae at various stages of
development. Cercaria (Fig. 118) with blunt cylindrical body, tapering
slightly a t posterior end, 0.155-0.230 mm (average 0.185 mm) long x
0.032-0.058 mm (average 0.040 mm) wide; tail stem of three lobes,
median lobe 0.066-0-073mm (average 0-070mm)long x 0~015-0~018mm
(average 0.017 mm) in diameter, lateral lobes 0.051 mm long x
0.016 mm in diameter ; long filamentous furcae highly contractile,
2-7.5 times length of body when extended, generally directly anteriorly ;
sucker-like structure a t free end of each lobe of tail stem; anterior
holdfast (referred to as a haptor by Giles) eversible and cup-shaped,
0.045 mm long, covered with small spines distally ; butterfly-shaped
cytogenous gland, 0.040 mm long x 0.035 mm wide, immediately
posterior to haptor; ventral oral sucker in posterior half of body,
0.014-0-016 mm in diameter ; intestinal caecum simple, sac-like,
0.031 mm long; two testes posterior to ventral sucker, right testis
0.018 mm x 0.010 mm, left testis 0.017 mm x 0.017 mm; cirrus pouch,
ventral to left testis, continuous with genital atrium on ventral body
surface immediately anterior to posterior body terminal ; ovary,
0.015 mm x 0.008 mm, dorsal to right testis and extends slightly
anterior to i t ; excretory vesicle extends from body-tail junction to
posterior edge of ventral sucker.
superfamily Bucephaloidea; family Bucephalidae)
Other injormation. Nothing else is knowB abmf C, n~bZ..i