242 THE NATURALIST IN AUSTRALIA. 
order, the separate companies it may be in different directions, as though amenable 
to strict military discipline. It commonly happens, moreover, that several larger 
male individuals lead the van 
of these moving battalions, and 
seemingly fulfil the 7é/e of com- 
manding officers. If followed 
at a little distance, they will 
continue their march at an sone Jog 
accelerated pace, but if over- 
taken or pressed hard, they ARMY CRABS, Mycteris longicarpus. NATURAL SIZE. 
will disappear beneath the surface of the sand almost as suddenly as they emerged 
above it. The body of these crabs being usually pale blue or lilac, and all the limbs 
light flesh colour, they constitute, when seen in masses under their characteristic 
auspices, a conspicuous feature in the landscape. 
The structural peculiarities of Mycteris distinguish it from all other crab 
genera, and indicate and explain the singular celerity with which its members burrow 
into or underneath the sand, 
together with their general 
adaptation to their sandy 
habitat. The body in these 
crabs is almost globose, but 
more dilated above. The 
so-called foot-jaws or ex- 
ternal maxillipedes differ 
from the usual formula in 
being set nearly vertical, 
are much the wider supe- 
riorly, and form in their 
conjoined condition an in- 
verted cone. When de- 
scending into or burrowing 
through the sand, the apex 
of this cone is driven fore- 
most; a spiral motion is 
W. Saville-Kent, Photo, _ 
ARMY CRABS, Mycteris platycheles. “A DESPERATE MELEE.” communicated to the body 
