SWIMMING CEABS. 187 



deoTees of minuteness, down to half a line. When 

 contracted, out of water, they presented a close resem- 

 blance to a glossy beetle — a Gyrinus^ for example ; but 

 in crawling the body was considerably elongated. 



In the Aquarium they are fond of crawling up the 

 side perpendicularly till they reach the surface, when 

 they float back downward, or more generally let go, 

 bend in the foot, and drop at once to the bottom. 



THE FIDDLER. 



Beneath a large flat stone, exposed at extreme low 

 water, at the end of one of the low rough ledges 

 that run out from the foot of Byng Cliff, I found in 

 September a full-grown specimen of the Velvet Fid- 

 dling Crab [Poj'tunus inibei'). All the Crabs of this 

 family, which contains a great number of species and 

 not a few genera, are distinguished at once by a pe- 

 culiar modification of the hindmost pair of feet, for 

 the performance of an important function. They are 

 all Swimming Crabs ; and the facility with which they 

 can roam through the element they inhabit, depends 

 largely on the completeness of the modification which 

 I refer to. Our common eatable Crab, the bulky, 

 thick-clawed, livid 8-pounder, that lies with all his 

 ten pairs of feet so meekly folded across his breast, can 

 swim — about as well as a stone of the same size. 



Now examine his hindmost feet ; their single toe 

 tapers to a sharp point, in no wise differing from 

 those of the four pairs that precede them. But the 

 Portunidoe, or Swimming Crabs, have this last pair of 

 feet much flattened out sidewise, and the toe in par- 

 ticular dilated into an oval, thin-edged plate ; which, 



