6. THE PHYLUM PROTOZOA
159
does not take place in the mollusc and presumably occurs in another
host which is still unknown.
Other information. In addition to being found in the nephridia of
clams, LBger and Duboscq (1915) have reported that P. glomerata also
occurs in visceral ganglia and in ducts leading from the nephridia. At
these sites, the macro- and microgametocytes are found either penetrating or within individual cells. When a young gametocyte first
enters a host cell, the latter becomes enlarged and extends beyond the
normal cell level (Fig. 48) ; however, in time the parasite-enclosing cell
is retracted into position although it is hypertrophied and its larger
size causes the compression of adjacent cells. The space normally
occupied by the cytoplasm in parasitized cells is entirely occupied by the
parasite. The nucleus becomes hypertrophied and gradually disappears.
If the infection is intense, individual parasites, enveloped by their
host cell, will join with one another and thus five to ten parasites can be
seen aggregated in the host’s renal cavity (Fig. 49). ItJ is for this reason
that the specific name “glomerata” was proposed to describe such
aggregates.
There is no information available relative to the fate of parasitized
clams; however, there is no reason to believe that P. glomerata is
lethal to Tapes. Similarly, there is no information available on the
infectivity of P. glomerata to man, although there is no reason to
believe that this parasite is of any public health significance.
6. Pseudoklossia pectinis LBger and Duboscq, 1917. (Figs. 50-52)
(Subclass Coccidia; order Eucoccida; suborder Eimeriina; family Aggregatidae)
Pseudoklossia pectinis is the only other species of this genus known
to parasitize a marine pelecypod. The other two known species, P.
patellae and P. chitonis, parasitize the hepatopancreas of the marine
prosobranch Patella and the digestive tract of the chiton Acanthochites
fascicularis respectively (Debaisieux, 1922). A fifth, but doubtful,
species, P. legeri, was reported by Harant (1931) from the pyloric
gland of the ascidians Styela and Polycarpa. P. pectinis was reported
by LBger and Duboscq (1917) from the nephridia of the scallop Pecten
maximus in France.
Anisogamy and sporogony in
molluscan host ; young microgametes elongate, 10-1 1 p long ; macrogamete pyriform, 36-38 p long, 24 p wide ; oocyst (or zygote) spherical,
32-35 p in diameter, includes elongate sporozoites typically grouped
in pairs (Fig. 50) ; spore membrane not seen ; each sporozoite measures
3-5 p in diameter.
Description of stages in mollusc.
159
does not take place in the mollusc and presumably occurs in another
host which is still unknown.
Other information. In addition to being found in the nephridia of
clams, LBger and Duboscq (1915) have reported that P. glomerata also
occurs in visceral ganglia and in ducts leading from the nephridia. At
these sites, the macro- and microgametocytes are found either penetrating or within individual cells. When a young gametocyte first
enters a host cell, the latter becomes enlarged and extends beyond the
normal cell level (Fig. 48) ; however, in time the parasite-enclosing cell
is retracted into position although it is hypertrophied and its larger
size causes the compression of adjacent cells. The space normally
occupied by the cytoplasm in parasitized cells is entirely occupied by the
parasite. The nucleus becomes hypertrophied and gradually disappears.
If the infection is intense, individual parasites, enveloped by their
host cell, will join with one another and thus five to ten parasites can be
seen aggregated in the host’s renal cavity (Fig. 49). ItJ is for this reason
that the specific name “glomerata” was proposed to describe such
aggregates.
There is no information available relative to the fate of parasitized
clams; however, there is no reason to believe that P. glomerata is
lethal to Tapes. Similarly, there is no information available on the
infectivity of P. glomerata to man, although there is no reason to
believe that this parasite is of any public health significance.
6. Pseudoklossia pectinis LBger and Duboscq, 1917. (Figs. 50-52)
(Subclass Coccidia; order Eucoccida; suborder Eimeriina; family Aggregatidae)
Pseudoklossia pectinis is the only other species of this genus known
to parasitize a marine pelecypod. The other two known species, P.
patellae and P. chitonis, parasitize the hepatopancreas of the marine
prosobranch Patella and the digestive tract of the chiton Acanthochites
fascicularis respectively (Debaisieux, 1922). A fifth, but doubtful,
species, P. legeri, was reported by Harant (1931) from the pyloric
gland of the ascidians Styela and Polycarpa. P. pectinis was reported
by LBger and Duboscq (1917) from the nephridia of the scallop Pecten
maximus in France.
Anisogamy and sporogony in
molluscan host ; young microgametes elongate, 10-1 1 p long ; macrogamete pyriform, 36-38 p long, 24 p wide ; oocyst (or zygote) spherical,
32-35 p in diameter, includes elongate sporozoites typically grouped
in pairs (Fig. 50) ; spore membrane not seen ; each sporozoite measures
3-5 p in diameter.
Description of stages in mollusc.