70 INVEBTEBRATE ANIMALS. 



The arrangement of M. Edwards is followed in the 

 retention of Galatheidce in the tribe Macroura. 

 Estimated number of species : recent, 18 ; British, 5. 



IT Examples of Scyllarus, Ihaciis, and Galathea ; 

 and of j^glea Icevis, a fresh-water species from Chili, 

 collected and presented by Capt. J. A. Perry. 



Tribe ANOMOURA. oivoiJiog, irregular ; oupa, a tail. 

 The Crustacea of this tribe exhibit an advance in 

 organisation, the anterior or cephalo-thoracic portion of 

 the body being more developed in comparison with the 

 abdominal portion than in the Macroura. 



Group 173.— Section ANOMOURA INFERIORA (Dana) in 

 part. 



Sub-tribe PAGURIDEA. Hermit-Crabs. 



In the Soldier-crabs, or Hermit-crabs, the abdomen 

 is long, weak, and tender ; it is therefore inserted into 

 the cavity of some cast-off marine shell, of which the 

 crab becomes the tenant, changing however its habita- 

 tion for a more commodious one as it increases in size. 

 Shells occupied by P. Prideauxii, a British species, 

 very frequently afford a resting place for the Sea Ane- 

 mone, Adamsia macidata. Within the shell, together 

 with the crab, a beautiful sea-worm. Nereis hilineata, 

 often resides, seizing and devouring without molestation 

 a share of the food captured by the crab. 



The Purse- crab, Birgus latro, inhabits many islands 

 in the Pacific, living in holes at the roots of trees, and 

 only occasionally visiting the sea. It feeds on the nuts 

 of various palms, and is said to climb the cocoa-nut 

 trees in search of its favourite food. 

 Estimated number of species : recent, 43 ; British, 10. 



H Examples of Cenobita, Calcinus, &c. 



