LOBSTERS, HERMIT CRABS, AND CRABS. 537 



In the Pdlinuridce, or Spiny Lobsters, the outer pair of antennae are much 

 thickened at the base, but are destitute of a scale. The legs are short and 

 all end in simple claws ; the abdomen is broad. These 

 animals resemble lobsters in size and appearance, but the Spiny Lobsters, 

 shell is very hard and spiny. They are numerous in the 

 Mediterranean, but are not common in the colder seas of Northern Europe. 



Sub-Order II. Anomura. 



This section is often included with the Macrura, but may conveniently be 

 treated separately. The abdomen is more or less reduced ; it is soft, and its ap- 

 pendages are rudimentary ; the hinder legs are also frequently much reduced. 

 The front pair of legs is armed with strong pincers, and the outer antennae 

 are long. The animals generally burrow in the sand, or live in the shells of 

 molluscs. They are more abundant in warm countries than in cold. 



The following are the two most interesting families : 



In the Birgidce the abdomen is hard above, and pouch-shaped at the ex- 

 tremity. The cephalothorax is broad, and angulated in front. The type of 

 this family, Birgus latro (Herbst), is a very large Crustacean, 

 measuring over two feet in length ; it is of a blue colour. It Bobber Crabs. 

 is common in the Eastern Archipelago. It is amphibious, 

 and is said to climb trees in search of cocoa-nuts, which it is strong enough 

 to denude of the husk, when it contrives to force in the eye-hole, and to 

 extract the contents with its pincers. 



The Paguridce, or Hermit Crabs, have a very soft abdomen, and take up 

 their abode in empty univalve shells. Several common species inhabit our 

 shores, and may often be seen ensconced in whelk-shells, etc., 

 into which they retreat as far as possible on the least appear- Hermit Crabs. 

 ance of danger. In Tropical countries they grow to a much 

 larger size ; and some of them are land -animals, and inhabit land-shells, such 

 as Helix and Bulimus. 



Sub-Order III. Brachyura. 



This section includes the Crabs proper, in which the cephalothorax is short 

 and broad ; and the short abdomen, which has usually no tail-fin, and ia 

 narrow in the male and broad in 

 the female, is curved under the 

 cephalothorax. In the males th ere 

 are one or two pairs of abdominal 

 feet, and in the females five. 



The Porcellanidce are repre- 

 sented in England by one or two 

 species, the commonest of which 

 is the Porcelain Crab, Porcellana 

 platycheles (Tennant), a polished 

 flattened crab, of a reddish brown Fig. 11. SPIDER CRAB (Maia Squinado). 



colour, with very large broad 



claws. It is nearly round, and about two inches in length ; and is common 

 under stones near low-water mark. 



