THE DECAPOD CRUSTACEA. 195 



as true crabs the forms showing the characters mentioned 

 above, Atelecydus being excluded because of the long 

 antennae. 



Of the true crabs we shall consider here only three 

 families, into two of which most of our British forms 

 fall. 



The first family is that of the spider-crabs, or triangular 

 crabs, as the Germans call them. There is generally no 

 difficulty in recognising at once the British members of this 

 family. Its scientific name (Oxyrhyncha) refers to the 

 pointed rostrum which forms the anterior angle of the 

 three-cornered carapace. The popular name of "spider" 

 refers to the way in which the small body is suspended on 

 the long spidery legs. Spider-crabs differ, however, very 

 markedly from their terrestrial namesakes in regard to 

 their movements; far from being agile, they rival the 

 historic tortoise in the slowness and deliberation of their 

 methods of progression. Whether the sea-grass grows 

 beneath their feet or not, it is impossible to say; but it 

 certainly does grow freely on their backs, most of them 

 carrying about with them a perfect forest of weeds and 

 sea-firs. 



Our largest spider-crab is Maia squinado, the great " sea- 

 spider," spiny spider-crab, or devil's crab of the South and 

 West. It is collected in large quantities as an article of 

 food in the South-west, and is also abundant in the Medi- 

 terranean, where it was well known to the ancients. The 

 colour is reddish brown, but in life, as in other spider-crabs, 

 the body is usually densely clothed with seaweed and zoo- 

 phytes, attached by means of numerous bristles. The 

 carapace is ovoid in shape, and prolonged anteriorly into a 

 bifid rostrum with diverging horns. Besides the covering 

 of bristles, its surface is furnished with numerous tubercles, 

 and is strongly spinous at the margins. As in crabs in 

 general, the lowest joint of the stalk of the antenna is 

 firmly fused to the carapace. The abdomen is seven-jointed 

 in both sexes. The carapace may attain a length of eight 

 inches, and then would be about six inches broad, the legs 

 having a span of fifteen inches. If specimens both of this 

 crab and of the stone-crab (Lithodes maia, p. 187) can be 

 obtained, it will be found a very useful exercise to contrast 



