74 Part second. 



into a corner. The strong Eriphise are especially ready to fight , and 

 with their strong claws they pinch violently every thing which is held 

 out at them. In the Aquarium they have been seen to break thick glass 

 tubes. 



Out of the water all Shore-crabs can live a considerable time and 

 move about with as much agility as in their native element. 



Besides all these Crustaceans with five pairs of legs (Decapoda) we 

 must refer to a genus belonging to the Stomatopoda. This is the Man- 

 tis-prawn (Squilla mantis , Fig. 148) a slender, agile, and predacious 

 animal which in the shape and position of its claws greatly resembles 

 a well known insect, the Praying Mantis (Mantis religiosa). Its legs have 

 claws that close like the blades of a penknife on its handle; and it can 

 dart them at its victim with great force and velocity, like the predacious 

 insect which it resembles. The Mantis-prawn is a very clean animal, 

 and almost constantly occupied in carefully cleaning all parts of its body. 

 It may be seen in all sorts of attitudes , performing its toilet. Now the 

 eyes and feelers, now the mouth and its appendages , now the legs and 

 joints of the body are brushed and stroked, till no foreign particle is left 

 adhering to them. 



Up to the present we have dealt with Crustaceans of considerable 

 size, which at once strike the eye; but now we must spend a little time 

 over their smaller kin. 



The large group of the Crustacea comprises such a variety of species, 

 that only those zoologists especially studying this group have a concep- 

 tion thereof, and by far the greather number of species are unsuitable 

 for exhibition in an Aquarium. This is due in part to their smallness, 

 often accompanied by entire transparency , so that they cannot be seen 

 with the naked eye; in part to their secluded habits. We must confine 

 ourselves to those more striking kinds which are occasionally exhibited 

 in the Aquarium. 



Almost all the year round most of the tanks, especially Nrs. 7 and 11, 

 contain swarms of very minute , lively shrimps , which play about over 

 the sand like a swarm of flies. These are not the young of some larger 

 shrimp, but fully grown animals, the Opossum-shrimps or Mysidea. They 

 are remarkable for having their organ of hearing quite in their tails and 

 each leg terminating in two prongs. The higher species of crabs have 

 such bifid feet at the earlier periods of their life and have probably 

 sprung from some animal similar to the Mysidea of to-day. 



Out of the group of the Isopoda (of which the wood-louse is a typical 

 example , being an Isopod which has taken to terrestrial life) visitors 

 may often see the parasitic kinds Anilocra and Cymothoa (Fish-lice) 

 fixed to various fishes. They are attached to the head, the eyes, and the 

 tail of the fish by means of their mouth-appendages and the sharp sickle- 

 shaped legs (7 pairs); or they are attached within the gills or the throat 

 of the fish and suck its blood; they may attain the length of a couple of 

 inches. They fix themselves so firmly that no endeavours of the tortured 

 animal can dislodge them. The females carry about their eggs in a special 

 brood-pouch, on the under surface of their body, till the young ones are 



