144 • THE SCOTTISH NATURALIST 



from Mr W. G. Banfield, Tenbury, Gloucester (June, 1914); 

 Mr Jno. Ellis, Walsall (July, 1914); Mr G. A. Clout, Maid- 

 stone (December, 1914); Mr H. Overton, Sutton Coldfield, 

 Warwickshire (February, 1915); and I have also collected 

 specimens in Cheshire, Warwickshire, Staffordshire, Oxford- 

 shire, Fife, and Perthshire. 



All the above specimens I have referred to O. asellus, 

 Linn., believing them to be immature forms of that species. 



In January last Mr R. Standen, of the Manchester 

 Museum, sent me numerous examples of a small form of 

 O. asellus from Arnside Knott, Westmoreland, collected 

 by him in March 1914. All these specimens are richly 

 tuberculated, oval in form, with the frontal margin of the 

 cephalon produced into a triangular lobe, and of a brownisJi 

 red colour (in alcohol). 



Excepting in colour, th'^se specimens agree very closely 

 with the immature specimens of O. asclhis received from the 

 Channel Isles, Isle of Wight, Gloucester, Warwick, etc. 



The external skeleton, including the oral appendages,, 

 has been subjected to a very careful examination ; and, com- 

 pared with the corresponding parts of a large and typical 

 example of O. ascHus, and excepting for the larger size of 

 the tubercles on the mesosomatic segments, I fail to find the 

 slightest difference from the type. Further, I have similarly 

 examined some of the light coloured forms, from the above- 

 mentioned localities, with like results. 



So far as I am aware, young forms of O. asellus are 

 always more or less tuberculated. I have carefully examined 

 hundreds of specimens, but have failed to find a single smooth 

 example. The frontal margin of the cephalon is always pro- 

 duced into a triangular lobe, the apex of which becomes 

 slightly more obtuse in older specimens, 



I am of opinion, therefore, that the form described by 

 Koch is, as already surmised by Prof. G. O. Sars, nothing 

 more than an immature example of 0. asellus, Linn., and has 

 no claim to specific rank. 



