52 
SURVEY OP THE INTERTROPICAL 
1821. effect of magic : upon our retiring and attentively 
July 29. watching the spot, these curious animals would 
re-appear as suddenly as they had before va- 
nished. We fired at several, but so sudden were 
their motions, that they generally escaped ; two 
or three only were procured, which appeared from 
their lying on the mud in an inactive state to 
have been asleep ; they are furnished with very 
strong pectoral and ventral fins, with which and 
with the anal fin, when required, they make a 
hole, into which they drop. When sporting on the 
mud, the pectoral fins are used like legs, upon 
which they move very quickly ; but nothing can 
exceed the instantaneous movement by which 
they disappear. Those that were shot , were 
taken on board, but on account of the extreme 
heat of the weather, they had become so putri- 
fied as to be totally unfit for preservation, 
so. The next day, the 30 th, was spent in exa- 
mining some bights in the narrow part of the 
channel near Gap Island, so named from a re- 
markable division in its centre, through which 
the high-tide flows, and gives it the appearance 
of being two islands. It was on this occasion 
that we explored Half-way Bay, where we were 
fortunate in finding good anchorage, and in which 
we also discovered a strait, that on a subsequent 
