SPIDER-CRABS 105 
fined, but there is often a well-developed preeocular and 
postocular spine. The basal joint of the second antennz 
is generally slender, sometimes moderately enlarged. The 
carapace varies in shape, being subtriangular, or trun- 
cately triangular or subpyriform, rarely suborbicular. 
The rostrum is simple or bifid, sometimes very short. 
The chelipeds never have the fingers excavate at the tips. 
The walking legs are sometimes very long. In both sexes 
the number of distinct segments of the pleon varies from 
four to seven. 
To this family belong nearly forty genera, three of 
which are included in the British fauna. 
Macropodia, Leach, 1814, meaning ‘long-foot, had 
been already called Macrépus by Latreille, but that form 
of the name was preoccupied. By Lamarck in 1818 it 
was named Stenorynchus, ‘narrow-snout, a very appro- 
priate name but without any title to supersede the earlier 
Macropodia of Leach. Just as the title of the tribe 
Oxyrhyncha ought in accordance with its Greek original 
to be spelt Oxyrrhyncha, so should Stenorynchus have been 
spelt Stenorrhynchus. Part of this correction has been 
adopted in the commonly used form Stenorhynchus, and 
naturalists have been so much tickled with the pleasing 
sound that, instead of leaving the monopoly of it to the 
Crustacea, they have employed it also among beetles, 
reptiles, birds, and mammals. The British species Macro- 
podia rostratus (Linn.) is described in Bell’s History under 
the name Stenorynchus Phalangiwm (Pennant). The 
specific name given by Pennant alludes to the resemblance 
which these crabs with long thin legs bear to the Pycno- 
gonids or Sea-spiders, and which has won for them the 
designation of spider-crabs. In spite of their long limbs 
they are a sluggish and slow-moving race, and in con- 
sequence are devoured in great numbers by other inhabi- 
tants of the sea. The fact that there are great numbers 
of them to be devoured shows that nature has not left 
them entirely without means of defence, of which some 
account will presently be given. Mucropodia longirostris 
(Fabricius), which Bell calls Stenorynchus tenwirostris 
