1917-18.] Period of Survival of Shore-Crab in Distilled Water. 19 
more marked in the two anterior limbs, forced the body of the animal into 
a sloping position with the anterior end downwards. The crab was thus 
enabled to turn over head first on to its back, in which position it remained 
till respiration ceased. Some of the animals immersed, however, were not 
found in this position. 
When examined post-mortem, the arthrodial membranes were tense and 
the carapace was considerably raised from the thorax. The abdomen was 
often found unflexed, and the softer tissues swollen. This swelling was 
not invariable, as some animals appeared perfectly normal. The weight, 
however, was found to have increased. The cardiac area of the carapace 
was then removed, when an excess of fluid was found in the pericardium. 
As already mentioned, the heart was still beating, though irregularly, and 
continued to do so, although exposed, for about an hour afterwards. The 
obvious explanation for these changes is oedema. Increase of the body 
fluid was evident in the condition of the pericardium, and would naturally 
cause tension of the joints and lifting of the carapace. Semi-flexion of the 
limbs is similarly explained. 
A number of crabs showing no evidence of respiratory or other move- 
ment were transferred to sea-water, and recovery resulted in a few. Similar 
observations were recorded by Tait. 
Loss of Salts. 
Examination of the immersion fluid showed definitely the presence of 
chlorides and traces of sulphates. The chlorides were estimated in a series 
of eight experiments by Mohr’s method. The following are the results : — 
Sex. 
Breadth. 
Weight. 
Duration of 
Survival. 
Chlorides in Immersion 
Water. 
Original. 
Increase. 
Per cent. 
Total. 
Post- 
Moult. 
F. 
5"2 cms. 
24-67 grms. 
2 "93 grms. 
3 hrs. 30 mins. 
0-026 
0-132 grm. 
F. 
43 „ 
14-90 „ 
1-50 „ 
3 ,, 30 ,, 
0-038 
0-112 „ 
M. 
5-2 „ 
2575 „ 
3"65 ,, 
4 ,, 30 ,, 
0-040 
0-206 „ 
Inter-Moult. 
M. 
6 '5 cms. 
62-60 grms. 
1 6 hrs. 00 mins. 
0-038 
0*472 grm. 
M. 
6-5 „ 
66-00 „ 
4-00 grms. 
17 „ 20 „ 
0-040 
0-521 „ 
M. 
5 - 4 ,, 
32-00 „ 
23 „ 40 „ 
0-040 
0-256 „ 
Pre-A 
[OULT. 
M. 
6‘6 cms. 
61 "60 grms. 
3 -40 grms. 
7 hrs. 40 mins. 
0-040 
0"489 grm. 
M. 
5-8 „ 
40-70 „ 
4-70 „ 
11 „ 30 „ 
0-038 
0-307 „ 
