100 THE LIFE OF CRUSTACEA 



while those of the female are quite short. The most 

 remarkable features of its organization, however, 

 have to do with its habit of burrowing in sand. The 

 antennae, which in most Crabs are extremely short, 

 are in this species as long as the body, and each bears 

 a double fringe of stiff hairs disposed along the upper 

 and under sides of the antenna, but curved inwards, so 

 that when the two antennae are brought together 

 parallel with each other, the hairs interlock and form 

 a long tube. At its base this tube communicates 

 with a space in front of the mouth, into which open 

 the channels from the gill chamber at the front 

 corners of the mouth-frame. The Crab burrows in 

 fine sand, and the process is thus described by Pro- 

 fessor Garstang : *' The Crab sits upright on the 

 surface of the sand; the elongated, talon-like claws 

 of the four hindmost pairs of legs dig deeply into the 

 sand ; the body of the Crab is thus forcibly pulled 

 downwards by the grip of the legs, and the displaced 

 sand is forced upwards on the ventral side of the 

 body by the successive diggings and scoopings of the 

 legs ; the slender chelate arms of the first thoracic 

 pair assist in the process of excavation by thrusting 

 outwards the sand which accumulates round the 

 buccal region of the descending Crab." In this way 

 the Crab descends deeper and deeper, until nothing is 

 visible above the surface of the sand but the tips of 

 the antennae. The antennal tube keeps open a 

 channel leading from the buried Crab to the water 



