Vol. rr Pha 8-9,] Biological Work of the ‘‘ Investigator.’’ 335 
merely dig out the sand and leave it lying in a small mound 
around the entrance to their burrow, but the smaller examples 
ith a 
Ordinarily the ‘‘ pattern ’’ is very simple, the sand balls 
being irregularly arranged round the entrance with two or three 
well marked paths running radially oucwards (Fig. 1), but in 
certain other cases, and frequently in some particular portion 
Fie. 2. 
of the sandy beach, these crabs arrange the sand-pellets in a 
sortie Laeger sometimes forming as many as six concentric 
es (Fig.2). These seins are not made one after the srining 
& pipes ing Se when the first had been completed, 
but all six would be menced siniultaneously and peetcolly 
continued round -_ fers until the pattern was complete 
For a long time I was unable to ascertain how the crab 
nidneeaenioes ehees > little pellets of sand. That they were not 
