1 98 CR USTA CEA. PART in. 



swimming fin, terminates in a pair of grasping organs. 

 In order to protect this soft-skinned tail, the Hermit 

 crab folds it up and thrusts it into some old empty shell, 

 clasps the column of the shell with its grasping organs, 

 draws in the rest of its body, and covers it with the 

 broad hands folded in such a manner as to close the 

 mouth of the shell, and to defend itself if attacked. It 

 holds so fast that it cannot be drawn out ; but, when in 

 search of food, it stretches out its mailed head and legs, 

 and walks off with its house on its back. However, it 

 sometimes comes out of its shell to feed, and, like some 

 other crustaceans, it holds its prey with one claw, and 

 tears it to pieces with the other. They are very pug- 

 nacious, and come out of their shells to die. The larvse 

 of the Paguridse undergo transformation, and they 

 moult when full grown. 



Stomapoda. 



The Stomapods are all swimmers; they have long 

 bodies with a carapace ; but it is so varied in form and 

 size, that no general description of it can be given. 

 They have external, instead of internal, organs of respi- 

 ration ; gills in the form of tuffcs are in some cases 

 attached to a few of the foot-jaws, but they are much 

 more frequently fixed to the basal joints of their swim- 

 ming feet, so that the blood in their capillary veins is 

 aerated through their thin skin as they float in the 

 water. In the Squilla mantis, or S. Desmarestii, mem- 

 bers of a genus of this family, the gills, which are 

 fixed to the basal joint of their last pair of feet, consist 

 of a long conical tube, on each side of which there are 

 numerous parallel tubes, like the pipes of an organ, and 

 each of these has a row of many long cylindrical fila- 

 ments that drag in the water. The mouth and its 

 appendages are similar to those of the common Deca- 

 pods, with the exception of the anterior jaw-feet, which 



