On a Variety of Poicellio scaber, Latr. 



IX. — On an interesting Varieti/ o/" Porcellio scaber, Latr. 

 By Walter E. Collixge,' M.Sc, F.L.S., F.E.S. 



Well-marked variations ainon<2;st the Britisli Terrestrial 

 Isopoda, apart from colour-variations, are by no means 

 common. To some extent tins is probably dae to the fact 

 that the different species have not received the same attention 

 as have those of other groups. 



I have recently received from Mi'. P. A. Aubin, o£ 

 St. Helier, Jersey, Channel Isle<, who has given me most 

 valuable assistance in my studies of the Channel Island 

 species, a very interesting variation, which I think is worthy 

 of recording. 



Porcellio scuher, Litr., var. aiibini, nov. 



Colour a creamy white, with a few small sepia or slaty- 

 coloured dashes. First segment of the mesosome strongly 

 convex, giving the head a somewhat tucked-in appearance. 

 The backward curve of the lateral plates less acute. Tubercles 

 fewer, less prominent, and more irregular in arrangement. 

 Distinct transverse ridge on the terguui of the last thoracic 

 segment. Lateral lobes of cephalon smaller and of a different 

 contour to type ; frontal lobe less prominent. Basal joint of 

 antennpe smaller. Uropoda : exopodite more contracted proxi- 

 mally, giving the appendage a more conical shape. 



Ilab. From wet moss growing on face of a road cutting 

 through shale; St. Helier, Jersey, Channel Isles. 



I have pleasure in associating with this interesting variety 

 the name of Mr. Aubin. 



I may mention that I have taken a very similar colour- 

 variety, ic'itJiout the above structural differences, in Cheshire, 

 Warwickshire, Worcestershire, and Staffordshire ; but, 

 holding the view that colour-variations, especially in the 

 Iso|;oda, are ff very little importance unless associated with 

 structural differences, 1 have not previously recorded them. 



