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THE SENTINEL-CRAB. 



to be to dart upon its prey, grasp it firmly with its sharply pointed and powerful claws, 

 and retain its hold until the unfortunate victim is quite fatigued and falls an easy prey. 

 It is not so handsome as the velvet fiddler, having none of the beautiful scarlet and azure 

 tints which decorate that species, and being mostly colored with different shades of 

 brown. 



OUR last example of this interesting family is the SENTINEL-CRAB, so called from its 

 extreme watchfulness and the wonderful manner in which its eyes are arranged so as 

 to explore objects in every direction, without needing to move, or even to raise itself 

 from its flat and crouching attitude. The generic name of this creature is of Greek 

 origin, being composed of two words, the former signifying a foot, and the latter an eye, 





NIPPER-CRAB. Polfblus Henslowil. 



SENTlNEL.CRAB.-Podoptfj/nji/s vigil. 



and is given to it on account of the strangely long footstalks on which the eyes are 

 set. The figure represents the animal as it appears when alarmed, or when it desires 

 to look around it, the eyes being lifted so as to command an extensive view. When 

 the creature is at rest, the footstalks lie horizontally upon the body, and are received 

 into two channels or grooves where they lie hidden and safe from danger. These 

 grooves may be seen on reference to the illustration. 



A somewhat similar disposition is found in some of the land-crabs, but differing in the 

 arrangement of the footstalks. Each of these curious organs consists of two pieces, and 

 in the Sentinel-crab the first is long and the second very short, while in the land-crab 

 exactly the reverse takes place, the length of the footstalk depending on the second 

 joint. Only one species of Sentinel-crab is at present known, and is a native of the 

 Indian Ocean. It never attains very great size, its length varying from two to four inches. 



