SPIDER-CRABS 105 



fined, but there is often a well-developed pvEeocular and 

 postocular spine. The basal joint of the second antennte 

 is generally slender, sometimes moderately enlarged. The 

 carapace varies in shape, being subtriangnlar, 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 Macropus 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 Stetwrjnchus have been 

 spelt 8tenorrhynclius. Part of this correction has been 

 adopted in the commonly used form Stenorhynchiut, 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 PJmlangium (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. Macropodia longirostris 

 (Fabricius), which Bell calls Stenorynchus tenuirostris 



