Calcium and Phosphorus Metabolism of P. vigil — Sather 
197 
Fig. 2. Changes (mean ± S.E.) in the organic 
content of four tissues of P. vigil during the molt 
cycle. 
tion was composed primarily of exoskeleton, 
and so the values would probably approximate 
those of the carapace. It is apparent that the 
organic contents of the mid-gut gland, gill, and 
muscle increased during the proecdysial stages. 
The greatest inorganic fluctuation was found in 
the carapace. Only minor alterations were found 
in the other tissues. 
The calcium and phosphorus composition of 
the carapace, mid-gut gland, gills, muscle, and 
blood were determined. The results, based on 
dry weight, are plotted in Figures 4-8. In Fig- 
ures 4-7, the data are plotted as changes in per 
cent dry weight. The values for the blood 
(Fig. 8) are presented as mM/liter. 
The organic and inorganic composition of 
the exuviae were also determined. The results 
are illustrated in Figure 9. Also contained in 
this figure are the calcium and phosphorus con- 
tents of the exuviae, expressed as per cent com- 
position. 
The organic, inorganic, and calcium contents 
of the entire exuvia were compared with those 
found in the exuvial carapace; this information 
is summarized in Table 1. The carapace con- 
tained less organic material and less calcium 
than the entire exuvia. The mount of inorganic 
Fig. 3. Changes (mean ± S.E.) in the inorganic 
content of four tissues of P. vigil during the molt 
cycle. 
Fig. 4. Calcium and phosphorus content (mean 
± S.E.) of the carapace of P. vigil during the molt 
cycle. 
