86 Part second. 



are the crabs possessed of the capabihty of Autotomy, that is, 

 they can break off their legs at a particular spot near the base. 

 The lost limbs soon grow again. Out of the water all Shore-crabs 

 can live a considerable time and move about with as much agility 

 as in their native element. 



The Mantis Prawn (Squilla Mantis, fig. 146) belongs to the 

 group Stomatopoda which, although superficially resembling the 

 long-tailed Decapods, are really quite distinct. This crustacean 

 is named after the well-known Praying Mantis {Mantis religiosa) 

 owing to a similarity in the shape of the fore-limbs. These appen- 

 dages resemble the arms of a boxer ready for the fight. The 

 muscular joints, which, at rest, are folded in a zig-zag, can be 

 shot out suddenly and with great force so that the sharp, ivory- 

 hard and toothed terminal joint is deeply buried in the victim. 

 The Mantis Prawn has a long body composed of segments, the 

 suppleness of which is especially noticeable when it is cleaning 

 itself. This is done with two small brushes each on a long, thin, 

 jointed stalk. With these cleaning-organs, it brushes itself with 

 infinite care, often for hours on end, and 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. The female does not attach the eggs to the 

 abdomen but forms them into a little cake which she carries between 

 the mouth-parts until the young hatch out. This takes at least 

 two months and during that time she fasts. 



It is a well-known fact that it is difficult to find on land a 

 spot where there are no insects — even the best powder is often 

 powerless against them! In the sea the crustaceans replace these 

 ever-present animals. Even the species of the types described 

 above are very numerous and of world-wide distribution, but 

 of the untold masses of the smaller kinds belonging to the remain- 

 ing orders, the speciahst alone has any imagination. The seas 

 swarm with them, but they do not lend themselves to exhibition 

 in the Aquarium and so we will treat of some of them only, and in 

 a few words. 



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

 and II, contains 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, belonging to the group of Schizopods (split- 

 feet). Owing to their numbers and voracity they are dangers 

 to fish, especially those with naked skins {Lophius, Trygon) at 

 which they are continually nibbling. On the other hand young 

 fish delight to chase them, and in tanks where such are present 

 none of the little crustaceans are to be seen. The Schizopods 

 are characterized by having limbs resembling two-pronged forks. 

 The Decapods described above have also, in a very young stage, 



