454 THE POLISHED CRAB. 



namely, the very small and narrow snout, the round and flask-like body, the strong claw-feet, and 

 the very small size of the external antennae, which cannot be seen from the upper surface. A very 

 strange looking creature is the KEELED CRAB. It derives its name from the form into which 

 its carapace is moulded, being pinched, as it were, into a kind of keel throughout its length. 



In this crab the chief points of interest are the long arms and the apparently shapeless 

 carapace, which is moulded as if squeezed out of clay by a single grasp of the hand, and the 

 very long claw-feet. In consequence of this latter structure, the Japanese call one of the 

 species of this genus, the Tenko-gani, or Long-handed Crab. In this creature, as in the last, 

 there is no appearance of external antennae when viewed from the upper surface, the clawc are 

 feeble in proportion to the long and somewhat powerful limbs to which they are attached, and 

 the end of the carapace is drawn out into a long and sharp point. This species inhabits the ' 

 Philippines. 



THE Nut-crabs are members of the same family, and are found off the British shores. 

 PENNANT'S NUT-CRAB is generally to be caught in about fifteen fathoms of water. It is rather 

 a sluggish and inactive species, burying itself in the sand or mud at the bed of the sea, much 

 after the fashion of the toad, and only leaving its eyes and claws at liberty to act. Thus it sits 

 and waits for prey, behaving much like the ant-lion in its pitfall of sand. It seldom moves 

 about except at night, and even when it does travel, its motions are very slow and deliberate. 

 It is rather a pretty little crab, being of a tolerably bright yellow, with a red patch on the 

 snout. 



This, and other species of the same genus, are often found in the stomachs of marine fish, 

 and as the shell is very hard, specimens are discovered in a good state of preservation. 



In the course of the preceding pages we have seen many instances of curious structures 

 which seem to be wholly supplementary and of no use whatever to the creature. The very 

 fact of their existence is a proof that there is some use for them, although their office is so 

 obscure as to elude all present researches. Such a crab is the IXA CYLINDRUS. On each side 

 of the body is a large cylindrical projection, so that the extreme measurement from side to side 

 is nearly equal to three times the length of the body ; the claws are long and feeble, all the 

 force seeming to be thrown into the two projections. This crab is a native of several parts of 

 Asia, and is found both in India and off the Philippines. 



Another odd-looking crab, having its carapace scooped and grooved in a wonderful man- 

 ner, is the Nursia plicata. It is found in the Indian Ocean. 



But we will not forget to mention the SEVEN-SPINED CRAB, so called on account of the 

 seven sharp points that project from the carapace. There are several large species of this 

 genus, one of which has nine spines instead of seven. In this curious creature the arms are 

 longer and more slender than in the preceding species, and the claws at their extremities are 

 exceedingly delicate and feeble. This crab is a native of the Eastern seas, and is generally 

 captured off the coasts of India. 



Our next example is the MASK CRAB. It buries itself in the sand or muddy bed of the sea, 

 and only permits its snout to project, with the long antennae, so as to feel (or, as some suppose, 

 to listen) for approaching prey, and the eyes to look in all directions for any eatable creature 

 that may haplessly wander within reach, and the claws, in order to seize the prey when it 

 passes within the grasp of their long and formidable hands. 



The antennae are apt to become clogged with mud, and the crab is thereof gifted With an 

 apparatus whereby they can be perfectly cleansed. In order to effect this object, the crab 

 bends each antennae sideways, until it rests on the hairy base of its companion ; it then draws 

 it completely through the stiff bristly hairs, until every particle of extraneous matter is 

 brushed away. Sometimes the Mask-crab buries itself deeply, that it only leaves the tip of 

 the antennae above the sand. The name of Mask-crab is given to this crustacean, because the 

 carapace is so formed that its two waved grooves mould the surface into an obscure likeness 

 of the human face. 



In the genus of the POLISHED CRAB (so called from the smooth, shining surface of the 

 carapace), the carapace is somewhat heart-shaped, and very narrow behind ; the claw-feet are- 



