Peracarida — Isopoda . 4 o 



includes the species of Idotca common on the British coasts, one Table-case 

 of which is shown in a coloured drawing hung in Wall-case No. 6. '^°' ^^' 

 The family Arcturidae are remarkable for the long and sub- 

 cylindrical body, very unlike that of the ordinary Isopods, and 

 also for the great size of the antennae, on which the young cluster 

 as in the specimen of Arcturiis haffini (Fig. 25) exhibited here. 

 The Sub-order Oniscoidea comprises the familar " Woodlice " 



Piece of timber from Ryde pier, showing damage caused by Limnoria and 

 Gheliira. [Wall-case No. 4.] 



or " Slaters " so common in gardens. They are terrestrial animals 

 adapted for breathing air, and sometimes having, in the abdominal 

 limbs, tufted air-tubes like the " tracheae " of insects, which serve 

 as respiratory organs. The terminal limbs of the abdomen are 

 slender or minute, and the antennules are always small. The 

 large " Sea-slater," Licjia oceanica, which is alwaj'S found near the 

 sea and sometimes actually in rock pools, is intermediate in many 

 points of structure, as it is in habits, between the exclusively 



