936 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVllI. 
Figure 6 shows a form of masking brought about, not by deliberate action 
on the part of the crab, but through its pure passivity and slowness of move- 
ment. It is a Lambrus, whereon an oyster (Ostrea sp.) has settled, and grown 
so as to cover the whole of the carapace and the legs on the left side. This crab 
lives on pebbly bottom and when at rest with the chelipeds folded close to the 
body and the other legs tucked down, such an individual as this would look a 
worthless morsel to tackle. The association is of long standing, for on the ori- 
ginal oyster two younger ones have settled, together with over a dozen bar- 
nacles {Balanus). Lamhrus like Calappa shams death, when disturbed. 
