146 



Fishery Bulletin 98(1) 



3 and 4, Fig. 5). Total hemocyte density was signifi- 

 cantly depressed in infected crabs (Fig. 5A; 2-way 

 ANOVA by group and day, i^=5.03, P<0.001). Total 



hemocyte density was not significantly different 

 between crabs inoculated with different initial doses 

 (2-way ANOVA, 10'^ vs. 10'^ parasites per crab and 

 day F=3.19, df=l, 64, P=0.079). Crabs that were in- 

 jected and did not^acquire the infection ("immune" 

 hosts) did not have significant decreases in hemocyte 

 densities (Table 3, Fig. 5; 2-way ANOVA, F=IA6. df = 

 13, 105, P=0.145). In the early infection experiment, 

 the decrease in total hemocyte densities occurred 

 within three days of inoculation (Table 5). 



In addition to a decrease in cell density, the pro- 

 portions of different host cell types (density of cell 

 type divided by total hemocyte density) in infected 

 crabs shifted to those with proportionally more gran- 

 ulocytes than hyalinocytes (Table 6, Fig. 5, B and 

 D) (2-way ANOVA, i^=1.83; df=20, 149, P<0.05). Sig- 

 nificant shifts in the population of semigranulo- 

 cytes were also noted (F=2.5l, df =20, 149, P<0.001). 



