A WOODLOUSE NEW TO THE SCOTTISH FAUNA 251 



PORCELLIO RATZEBURGII, A WOODLOUSE 

 NEW TO THE SCOTTISH FAUNA. 



By Walter E. Collinge, D.Sc, F.L.S., Carnegie Fellow, and 

 Research Fellow of the University of St Andrews. 



SINCE the issue of the "Check-List of British Woodlice" 1 I 

 have continued to receive examples of these Crustacea from 

 all parts of Scotland. As a result Porcellio Icevis, Latr., and 

 P. rathkii, Brandt, have been added to the Scottish fauna, 

 and I have now the pleasure of placing on record two 

 localities for P. ratzeburgii, Brandt, thus completing the 

 list of the genus Porcellio, all six species having now been 

 recorded. 



The first examples were received from Miss M. J. 

 Jardine, from Helensburgh, Dumbartonshire, who also sends 

 specimens of Philoscia muscorum (Scop.), Porcellio dilatatus, 

 Br., Porcellionides pruinosus (Br.), and Armadillidium 

 vulgare (Latr.). Miss Jardine also very kindly sent me a 

 large collection of living examples of tiny, white, newly 

 hatched P. rathkii. At first I was doubtful of the species, 

 but after a moult or two these were seen to be referable 

 to P. rathkii, and I was enabled from these specimens to 

 establish a very interesting point, viz., that the fiagellum 

 of the antenna in the young examples is exactly like that 

 found in the adult of P. ratzeburgii, but after a few weeks 

 the proximal joint increases in size. I mention this fact 

 as it seems to me very risky to identify immature specimens 

 as P. ratzeburgii. 



For the second record I am indebted to the kindness 

 of Mr Magnus Spence of Deerness, Orkney, who forwarded 

 a collection of Porcellios, amongst which there were 

 numerous examples of P. ratlikii, and a single adult 

 specimen of P. ratzeburgii. 



I have carefully compared this latter with examples in 

 the Natural History Museum of University College, Dundee, 

 received from the distinguished Parisian Isopodist, M. 



1 Scot. Nat., 1917, pp. 111-116. 



