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datory animal, which in many respects reminds one of the Mantis 

 religiosa, or praying mantis, a land grasshopper. Its legs espe- 

 cially which are provided with pointed claws that snap 

 like the blades of a penknife, and can be darted at the victim 

 with great velocity and strength resemble those of the Mantis. 

 The Squilla is a very clean animal, and almost constantly oc- 

 cupied in carefully cleaning all parts of its body. It may be 

 seen making its toilette in all sorts of attitudes. Now the eyes 

 and feelers , now the mouth and its parts , now the legs and 

 segments of the body are brushed and stroked till no foreign 

 particle is left adhering to them. The object of this scrupulous 

 cleanliness noticeable in many crabs and insects (for instance, 

 the common housefly) is scarcely aesthetic, we rather suppose 

 it to be a very practical one the preservation of the different 

 delicate sense-organs. 



The great army of crabs of the lower order of the variety 

 of whose shapes the naturalist alone has till now the slightest 

 notion is far less adapted for exhibition in an Aquarium than 

 the higher Crustacea. This is partly owing to the small size 

 of most kinds , which is often combined with complete trans- 

 parency , so that they can only be seen with a glass ; and 

 partly to many being parasitic and hidden in the intestines of 

 other animals. We must therefore confine ourselves to mention- 

 ing the most striking of those now and then to be found in 

 the Aquarium, aiding our discriptions by explanatory remarks. 



The visitor will often find, sticking to some fishes, especially 

 to the wrasse, the parasitical species Anilocra and Cymothoa, 

 belonging to the sub order of the Isopoda, for which the well- 

 known wood-louse a crab converted to a life on land may 

 serve as a type. They fasten themselves into the head , the 

 eyes, or the tail-fins of a fish, boring into it with their mouths 

 and the sickle-shaped claws of their seven pairs of legs; or they 

 are found in the gills and throat of their victim. The Anilocra 

 attains a length of about an inch and a half. These animals 

 hook themselves so firmly to their victims that no effort of the 

 tortured animal can shake them off. The female parasite carries 

 her brood in a particular place on her belly until the young 

 are ready to creep out. 



Most species of the group Hay -crabs or Amphipoda - of 

 which the reader is perhaps acquainted with the Gammarus 

 pulex or common flea-crab that lives by thousands under the 

 pebbles of running brooks live in the sea. The north and 

 arctic seas especially are so full of these active little animals 



