594 



THE URANIA-CRAB. 



limited. A very few examples have been recorded where a limb has been lost and re- 

 placed, but such phenomena are extremely rare, and can only be looked upon as varia- 

 tions from the usual system. 



THE faculty of avoiding danger by closing all the joints of the limbs and merging 

 them as far as possible under the carapace, is carried to a wonderful extent in the 

 TORTOISE-CRAB, a crustacean that derives its popular title from its general similitude 

 to the reptile from which it derives its name. There are, indeed, many of the tortoise 

 tribe which are not able to enclose themselves nearly so perfectly as does this crab, and 

 excepting the box-tortoise, there is perhaps none that exceeds it in the very perfect con- 

 cealment of all vestige of their limbs. The carapace is wide, flattened at the edges, 

 and dome-like in shape, so as to afford a perfect cover to the limbs. Owing to the 

 manner in which these crabs conceal their limbs, Cuvier called them by the appropriate 

 name of Cryptopods, or Hidden Feet. In all of these creatures the carapace is domed 

 or vaulted, so as to form a shelter for the legs, while in the typical genus the claw-feet 



TORTOISE CRAB.-Camara Calappa. 



are very large and compressed, with a decided upper edge which is notched or toothed 

 so as to form a crest. The French know these crabs by various names, such as Mi- 

 granes, Coqs de mer, and Crabes honteux. 



The claws are broad, flattish, notched at the edge, and scooped in a peculiar fashion, 

 so that when folded over the body they exactly fit to the shell, as if they were part of 

 the same piece. Two sides of this species are given in order to show the crab in its 

 upper and under aspects. The Tortoise-crab is a native of the Mauritius. 



IN the family of the Leucosiidae, the carapace is more or less rounded, and projects 

 somewhat in front. 



The larger figure on the accompanying illustration represents the URANIA-CRAB, an 

 example of the typical genus. It has a smooth carapace with rounded edges, and the 

 claw limbs are very large and powerful in proportion to the size of the body. On their 

 edges they are covered with rounded tubercles, and one or two of these projections are 

 scattered upon the surface of several joints. In all these crabs, the apertures through 

 which water passes to cover the gills are in the form of canals. One curious characteristic 

 of these crustaceans is that the external antennae are very small indeed, and are inserted 



