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clumps in the ovary to foci in the leydig tissue of the testes. Nineteen
(86.4%) of the cases were in female gonads. Reproductive stages
varied from undeveloped to spawned. Three of the cases were found in
testes.
In the general and focal leucocytoses discussed above, the difference
between the two was in the extent (small area, tight clump vs.
general dispersion over several follicles) of inflammation, but this
was sometimes difficult to ascertain and the two may blend together.
Necrotic appearing areas were noted in 3.1% (4 of 130) of the gonads
examined. These areas were characterized by cellular debris, degenerating
ova, and leucocytosis.
Sporozoa were present in 4.6% (6 of 130) of the specimens examined.
Sporozoans were spherical, densely staining, and were embedded in the
gonadal tissue. The specimens appeared to be surrounded by a small lysed
"halo" area.
5. Gill . - Gills from 134 C. gigas were examined for pathologies.
Generally, three pieces of gill (consisting of both lamellae) were
dissected from one side and oriented (when possible) to give both longitudinal
and transverse sections.
Histopathologies were noted in 31.3% (42 of 134) of the gills
examined. There were a total of 49 cases of the six pathology types
described below. Forty-three (87.8%) were apparently not symbiotic or
related to a symbiotic condition.
. Abnormally high numbers of eosinophilic leucocytes were present in
31.3% (42 of 134) of the gills examined. In most incidences, the leucocytes
were dispersed throughout several plica, but four cases appeared
to be more focally organized in one or two plica.
Amoebae were noted in the gills of one C. gigas. The infection
appeared to be light as only two amoebae were found. The amoebae were
circular in outline with a hyaline cytoplasm. The nucleus occupied
approximately one-third of the cell. A small, spherical inclusion
body was adjacent to the nucleus.
The gills of four (3%) specimens examined harbored ciliates in
their water tubules. Ciliates were somewhat crescent-shaped with tufts
of stout cilia extending downward from the two tips. The arms of the
crescent were sometimes turned inward so that the tips of the cilia were
touching, giving a partially hollow, circular shape to the ciliate. Two
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