clumps in the ovary to foci in the leydig tissue of the testes. Nine- 

 teen (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 differ- 

 ence 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 longi- 

 tudinal 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 leuco- 

 cytes 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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