BEESTON : ADDENDA TO GRANGE MOLLUSCA. 33I 



Balea perversa (I.inne). — Common on mossy walls at Rigland 

 Scar, Holker, September, 1908 (J.W.J.). 



Clausilia bidentata (Strom). — Common on walls at Bigland 

 Scar ; Cark ; Flookburgh. 



var. cravenensis Taylor. — Very abundant, along with type. 

 No intermediate forms. I consider this a good species. Bigland 

 Scar; Cark, September, 1908 (J.W.J. ). 



Pisidium obtusale Pfeiffer. — Common in ponds on Hampsfell, 

 September, 1908 (J.W.J. ). 



Pisidium nitidum Jenyns. — Common in ponds on Hampsfell, 

 September, 1908 (J.W.J.), 



On a habitat of Acicula lineata. — Although I have been able to get Acicida 

 Uneata in small numbers for years past in Hackness, Forge Valley and Yedmandale, 

 I have altogether obtained but few, by far my best result being sixteen in one day. 

 This spring I have got it in larger numbers, and I think the information might be 

 of service to other members of the Society who have overlooked one of its habitats as 

 I have done. In Forge Valley, near Scarborough, are one or two boggy places 

 where Pupa anglica can be had in numbers. In these bogs grows in abundance the 

 moss Stereodon ciipressiforvie Mitt., which is a plant well known to be affected by 

 this species, as at Shipley Glen, near Bradford, various places on the coast between 

 Speeton and Ravenscar, and elsewhere. In all these places the moss is kept damp 

 by percolating water, and a luxuriant growth is the result. In Forge Valley, the 

 underlying stratum is a calcareous tufa, deposited by the water surcharged with 

 calcium carbonate. When broken, this tufa yields Succinea putris, Ccchlicopa 

 lubrica, Livnia'a iruncatiila, Sec, all, however, as far as I know, being recent species. 

 Where the moss is very luxuriant and thick, a dense mass of rootlets forms of a dark 

 brown, almost blackish colour, and in these dense masses Acicula lincala occurs. 

 Continuous searching in the moss yielded only one or two specimens, but on looking 

 at the roots, better results were obtained at once, and on taking home a paper bag 

 full and turning it over at intervals during two or three days, over forty specimens 

 were obtained. Later examination confirms this habitat, and I think it probable 

 the species may be found in similar positions elsewhere. Most of the specimens 

 were dead, but in excellent condition, and quite clean. Presumably the Acicula 

 were hibernating in the roots, and died, or were attacked and devoured by the other 

 numerous inhabitants of the bog. In company with Acicula were Helix lamella/a, 

 H. fusca, H. granulala, H. horlensis, H. arbtistoruvi, H. roiiiiidala, Hyalinia 

 alliaria, Hy. piira, Hy, crystalliiia. By. cellaria, Hy. nitiiiula, Hy. radiatttla, 

 Enconttliisfiilvus, Succinea put jis, Vertigo edentula,Jamiiiia muscoruin, Carychiui/i, 

 Avion aler, A. fascial us, Umax Levis, and very abundantly Pupa atiglica, of which 

 one visit yielded over sixty specimens, whilst subsequent visits have produced even 

 larger numbers crawling on dead sycamore leaves. Perhaps for its size (it is only 

 a few yards each way) this is the most conchologically prolific piece of ground in 

 Yorkshire. My friend, Mr. Harman, was the first to find this particnlar habitat 

 for Acicula limala when we were searching for it together. — J. A. Hargkea\es 

 [Read before the Society, June 9th, 1909). 



