110 New York State Museum 



has means of protection. Masking, on the other hand, 

 may serve for the purpose both of defense and offense. 

 The long-legged Spider Crabs plant on their carapaces 

 seaweeds, sponges and hydroids which make them almost 

 invisible when they are in their natural environment. 

 Some sea anemones (Tealia) cover their bodies with bits 

 of shell and gravel to conceal themselves from their prey. 

 Certain crabs (Melia) carry sea anemones (Sagartia, 

 Bunodeopsis) around in their claws. The crabs carry 

 sometimes one species of anemone, sometimes another, 

 and will throw aside a small one of one species to take 

 up a larger one of another. The crab uses the anemone 

 for two purposes. If the crab is irritated it thrusts its 

 claws toward the direction of trouble placing the anemone 

 with its stinging nettles in the most favorable attitude of 

 defense or offense. In addition, the crab profits by the 

 food secured by the anemone. 



Certain animals have the power of autotomy (self- 

 amputation) and regeneration, that is, they can regrow 

 parts of the body which they have lost through acci- 

 dent or attacks of other animals, which is a form of 

 protection or defense. Among the crustaceans, such 

 forms as the prawns, lobsters and true crabs have the 

 power of throwing off the legs, which they do when 

 the limb is roughly held or crushed. These animals 

 may therefore be found with unequal claws or walk- 

 ing legs, while the process of regeneration is going on. 

 In starfishes and brittle stars there is self-amputation 

 of the arms. Starfishes can not only regenerate an 

 arm, but a single arm with a portion of the disc at- 

 tached can generate a whole starfish. That is why 

 starfishes are found with such unequal rays or arms. 

 Brittle stars may shed the arm in one piece, or the 



