STANDEN : ANCYI,US I'l.tl VIATILIS IN DERIIYSHIKE. 79 



cleaning out the shells, to find them practically white, with — in the 

 younger shells especially — a very pale diaphanous straw-yellow 

 epidermis. The shells are of medium size, thin, though not particu- 

 larly fragile, beautifully clean, semi-transparent, finely striate, and 

 mostly free from the extraneous growths of microscopic algse or other 

 organisms which so often disfigure the shells of Aficy/us, and there is 

 little trace of the erosion of the beak by humic acids which is prevalent 

 in many localities. 



The muscle scar midway up the shell is unusually well defined, and 

 presents the form of an irregular purple-black scroll, commencing 

 with an oval blotch, and extending nearly round the inner circum- 

 ference. This internal scroll shows up very vividly against the 

 shining white interior, and is plainly visible through the thin shells 

 on their dorsal surface — giving tliem an exceptionally curious appear- 

 ance which at once attracts attention. Neither of us remembered 

 having seen this peculiar mark before in any specimens we had 

 collected, and none in Mr. Taylor's collection showed it. I have 

 since examined my own series of Aticylus — which contains over forty 

 locality sets, exhibiting great diversity in both external and internal 

 colouration — and find that specimens from Malham Cove, and 

 Airedale, bear a mark precisely similar to the Dove Dale examples, 

 but it is much less plainly conspicuous exteriorly, owing to their 

 greater thickness of shell. 



Associated with the Ancylus were some small-sized, but extremely 

 globular Livuuea pereger. Numbers of enormous specimens of Arion 

 (iter — some of them the largest individuals we have ever seen — were 

 crawling over the watercress, together with a few small Sziccinea pntris. 



The variety gibbosa does not appear to have been hitherto recorded 

 for Derbyshire, and this fact, coupled with its assuming a white form, 

 and the presence of what seems an unusual and striking marking, 

 merits, in my opinion, more than a passing notice. 



Testacella scutulum in Staffordshire.— I have now to record another new 

 species of moHusca for our county, Testacdla scnttihim, having been identified by 

 Mr. B. Bryan of the North Staffordshire Field Chib Museum at Hanley, from speci- 

 mens recently obtained in a garden at Fenton, in the new federated Borough of 

 Stoke-on-Trent. The identity of the species has been confirmed by Mr. j. W. 

 Taylor, to whom I submitted the four specimens found. Mr. Bryan tells me that 

 the man from whom he received the slugs stated that he had seen many of them for 

 some years past in the garden, and frequently found them crawling over the walks 

 in the day-time, but he was ignorant what they really were until Mr. Bryan identi- 

 fied them as T. scutulum. — John R. B. Masefield {Read before the Society, 

 Nov. 13th, 1912). 



