THE DECAPOD CRUSTACEA. 201 



three teeth in the projecting forehead, and five in the 

 antero-lateral margin, which is much shorter than the 

 postero-lateral margin. The great forceps are short, the 

 hand has a double keel. The terminal joint of the last 

 pair of walking legs is slightly expanded and flattened. 

 As in the Cyclometopa in general, the abdomen is five- 

 jointed in the male, and seven-jointed in the female. 

 The females will be found not infrequently carrying the 

 bright orange eggs attached to the hairy abdominal 

 appendages. 



The next crab is one which is much more likely to be 

 found on the shore after storms than living under natural 

 conditions. This is Portumnus variegatus, a peculiar little 

 swimming crab, common off sandy shores, and easily recog- 

 nised at a glance by the shape of its carapace. This is 

 peculiar in being as broad as it is long, the antero-lateral 

 and postero-lateral margins being rounded instead of meet- 

 ing at a sharp angle. The last walking leg is, as in the 

 next genus, but to a less extent, converted into a swimming 

 paddle, the terminal joint being broad and flattened, and 

 the penultimate broad, rounded, and compressed. This 

 crab, which has no English name, is a beautiful little 

 creature, of mottled purplish white tint. 



Finally, we come to the large genus Portunus, including 

 the true swimming crabs, popularly called "fiddlers" from 

 the peculiar motion of the last pair of legs. These ap- 

 pendages are completely converted into swimming paddles, 

 and enable the crabs to dart rapidly through the water, 

 thus taking on the function exercised in ancestral forms by 

 the tail. In general shape the fiddlers resemble the shore 

 crab, the carapace bearing similar teeth on its margin, but 

 it is much flatter and slightly different in its details. The 

 legs, and especially the great claws, are beautifully marked 

 and sculptured, the swimming crabs being alike in colour 

 and form singularly beautiful creatures. 



The largest species is the velvet-crab (Portunus puber\ 

 which owes its name to the dense coat of fine hair which 

 covers the body. It is very rare on the East Coast, but is 

 abundant on the South-west, where it occurs among weeds 

 between tide-marks. 



There are numerous other species of swimming crabs, 



