282 THE SEA SHOEE 



resemble the last species, and belong to the same genus, but the 

 others are very different in general appearance. The Northern 

 Stone Crab (Lithodes), found principally on and off the coasts of 

 Scotland and Ireland, has a spiny covering with a long beak. 

 Another species Dromia vulgaris is somewhat similar in habit, 

 though it can hardly be termed a stone crab, since it inhabits deep 

 water, and apparently lives among the sponges, sea firs, and weeds ' 

 that cover the bottom. 



The remainder of the Peculiar-tailed Decapods belong to the 

 Soldier or Hermit Crabs, and constitute the genus Pagurus. 



Every one who has searched a few rock pools will have seen 

 the familiar Hermits, and will probably have been interested in 

 their varied antics. First you observe the shell of a mollusc a 

 Trochus, Periwinkle, or a Whelk travelling at an abnormal rate 



FIG. 212. Dromia vulgaris FIG. 213. THE HERMIT CRAB IN 



A WHELK SHELL 



for a member of its class. You approach closely to make an 

 inquiry into the matter, when the motion suddenly ceases, and the 

 shell instantly drops into position with its mouth close to the sur- 

 face below. If left undisturbed for only a short time, the rapid and 

 somewhat jerky motion is resumed, only to cease as suddenly as 

 before as soon as the inhabitant is again threatened. 



On examining the shell we find that it is the home of a species 

 of crab, and that the animal within it is completely hidden with 

 the exception of its head, stalked eyes and long, slender antennae, 

 one very large claw, and a few walking legs. 



To remove the creature from its home is no easy matter as a 

 rule. To pull it out by means of its legs or its antennae would 

 probably be to sever some portion of its body; but if you thrust 

 the creature, shell and all, among the spreading tentacles of a large 

 anemone, it will at once grasp the peril of the situation ; and, if 



