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NOTES ON TERRESTRIAL ISOPODS FROM NORTH 



DEVON. 



By Bruce F. Cummings. 



The Woodlice in Great Britain have been somewhat neglected, 

 and a great deal remains to be done by way of geographical distri- 

 bution. Also, there are very few recorded observations on their 

 habits, though they have received considerable attention from 

 anatomists. It is therefore with the hope of enlisting more field 

 observers of these crustaceans that I write the following few field 

 notes. 



I have found Messrs. Webb & Sillem's book, ' The British 

 Woodlice,' invaluable for identifying species, and it also contains 

 plates of all the British species. The Rev. Canon Norman has a 

 series of notes in ' The Annals and Magazine of Natural History ' 

 on " The British Land Isopoda." In January this year Mr. C. 

 Gordon Hewitt published a memoir on Ligia oceanica, which con- 

 stitutes No. XIV. of the Liverpool Marine Biological Committee's 

 series of memoirs. With these books at jonv disposal it is 

 possible to begin operations at once. Collecting Woodlice dove- 

 tails well with beetle-hunting, and I have often reprieved a 

 blank day with the Coleoptera by turning my attention to the 

 Woodlice, which are to be found in precisely similar localities. 



The process of the shedding of the outer cuticular layer in 

 different species of Crustacea has engaged the acute observation 

 and descriptive powers of many well-known naturalists, from the 

 classic records of the illustrious Reaumur, on the Crayfish, 

 onwards, and the process is no less interesting in the Wood- 

 louse. However, the following is by no means intended as 

 exhaustive, or even as a full account, but only some of my notes, 

 by the way, on moulting Woodlice. 



I took a specimen of Porcellio scaber last year, which began 

 moulting almost immediately. Previously it was sluggish, and 

 remained fixed to a clod of earth, though otherwise there was no 



