6 . THE PHYLUM PROTOZOA
153
each measures 3-4p in diameter. These become fusiform and a protective spore wall is laid down around each, forming a spore. Mature
spores, found primarily in the oyster’s gills, are ovoid, slightly pointed
at each end, and measure 15-20 p x 9-11 p. Each spore encloses a
sporozoite and represents the infective form for crabs.
Nothing is known about the ecology of N . prytherchi
except that concurrent infections with N . ostrearum commonly occur
in Crassostrea virginica.
Physiology. Nothing is known about the physiology of N . prytherchi
except that Sprague (unpublished) has reported that “ highly refractive
fat droplets occur in young sporozoites comprising gymnospores ”.
These are no longer apparent in mature sporozoites, thus suggesting
that these lipid droplets are utilized during maturation.
Pathology. Again, specific observations on pathological changes in
oysters and crabs parasitized by N . prytherchi have not been made.
Superficial observations, however, suggest that this parasite does not
injure its hosts to any great extent.
3. Nematopsis legeri (de Beauchamp, 1910). (Figs. 31-40)
Ecology.
(Subclass Gregarinia ; order Eugregarinia ; suborder Cephalina; family
Nematopsis legeri is a common parasite in a number of species of
marine molluscs including pelecypods, chitons, and gastropods.
Porospora galloprovincialis, described by LBger and Duboscq (1 925),
is a synonym. According to Hatt (1931), who has critically evaluated
the then known species of Nematopsis and those of the related genus
Porospora, N . legeri has been reported to parasitize the following
molluscs in European waters : Mytilus galloprovincialis, M . minimus,
Lasea rubra, Cardita calyculata, Chiton caprearum, Trochocochlea
turbinata, T . articulata, T . mutabilis, Phorcus richardi, Gibbula divaricata,
G. rarilineata, G. adamsoni, Pisania maculosa, Cerithium rupestre,
Columbella ristica and Conus mediterraneus. N . legeri has not been
reported from either North or South America. It has also not been
reported from Africa, Asia or Australia.
Description of stages in mollusc. Gymnospores, 7 p in diameter,
comprised of few large sporozoites ; spore, averaging 14-15 p long, with
distinct one-piece shell (endospore) and a less conspicuous epispore,
circular in cross-section.
Life cycle. The life cycle of N . legeri involves a crustacean definitive
host, Eriphia spinifrons (see Hatt, 1931), and a molluscan intermediate
host which may be one of the several species listed above.
Porosporidae)
153
each measures 3-4p in diameter. These become fusiform and a protective spore wall is laid down around each, forming a spore. Mature
spores, found primarily in the oyster’s gills, are ovoid, slightly pointed
at each end, and measure 15-20 p x 9-11 p. Each spore encloses a
sporozoite and represents the infective form for crabs.
Nothing is known about the ecology of N . prytherchi
except that concurrent infections with N . ostrearum commonly occur
in Crassostrea virginica.
Physiology. Nothing is known about the physiology of N . prytherchi
except that Sprague (unpublished) has reported that “ highly refractive
fat droplets occur in young sporozoites comprising gymnospores ”.
These are no longer apparent in mature sporozoites, thus suggesting
that these lipid droplets are utilized during maturation.
Pathology. Again, specific observations on pathological changes in
oysters and crabs parasitized by N . prytherchi have not been made.
Superficial observations, however, suggest that this parasite does not
injure its hosts to any great extent.
3. Nematopsis legeri (de Beauchamp, 1910). (Figs. 31-40)
Ecology.
(Subclass Gregarinia ; order Eugregarinia ; suborder Cephalina; family
Nematopsis legeri is a common parasite in a number of species of
marine molluscs including pelecypods, chitons, and gastropods.
Porospora galloprovincialis, described by LBger and Duboscq (1 925),
is a synonym. According to Hatt (1931), who has critically evaluated
the then known species of Nematopsis and those of the related genus
Porospora, N . legeri has been reported to parasitize the following
molluscs in European waters : Mytilus galloprovincialis, M . minimus,
Lasea rubra, Cardita calyculata, Chiton caprearum, Trochocochlea
turbinata, T . articulata, T . mutabilis, Phorcus richardi, Gibbula divaricata,
G. rarilineata, G. adamsoni, Pisania maculosa, Cerithium rupestre,
Columbella ristica and Conus mediterraneus. N . legeri has not been
reported from either North or South America. It has also not been
reported from Africa, Asia or Australia.
Description of stages in mollusc. Gymnospores, 7 p in diameter,
comprised of few large sporozoites ; spore, averaging 14-15 p long, with
distinct one-piece shell (endospore) and a less conspicuous epispore,
circular in cross-section.
Life cycle. The life cycle of N . legeri involves a crustacean definitive
host, Eriphia spinifrons (see Hatt, 1931), and a molluscan intermediate
host which may be one of the several species listed above.
Porosporidae)