2o8 ROEBUCK : ON DENBIGHSHIRE MOLLUSCA. 



Stones (some of them loose) are embedded in a profusion of 

 good limy mortar. The crevices of this wall yield a number of 

 species in abundance, such as Balea perversa and Helix rupes- 

 tris, with H. pulchella and its var. costata, Clausilia rugosa, 

 and Pupa umbilicata also in profusion. The woods near 

 yielded Carychium minimum, Zonites crystallinus, Helix pygmcsa, 

 &c. after much search. On the southern slopes of these hills, 

 about Llangwystenin, and in the more level country towards 

 Llandrillo-yn-Rhos, Rhos Fynach, and Colwyn Bay, a few odd 

 things were collected. 



Most of the collecting was done in the district which has 

 just been described, and which is wholly limestone, and the 

 only part of Denbighshire proper which was visited was along 

 the right bank of the Conway River. A walk of ten miles from 

 Llanrwst to Llansantffraid-glan-Conway, with the accompani- 

 m-ent of torrents of rain, was the occasion upon which were 

 collected the species cited for Llanrwst and Tal-y-Cafn. The 

 results were meagre, due more to the unproductiveness of the 

 Silurian slates than to the inclemency of the weather. It was 

 upon this occasion that I had the opportunity of collecting the 

 beautiful gelatinously translucent tree-slug, Limax arbormii, in 

 such numbers as I had never before seen it. It was under 

 nearly every stone in the beech woods which for a mile or so 

 bordered the road. 



The list subjoined includes 35 species and 12 varieties, a 

 small contribution towards a Denbighshire county fauna. I am 

 rather surprised that in a limestone district like that round 

 Llandudno I did not meet with more forms. I had quite 

 anticipated finding such things as Helix ericetorum, H. lapicida, 

 H. arbiislorum, Clausilia lamitiata, and Cochlicopa tridens. Nor 

 did I meet with any of the Vertigos, nor Zonites fiilvus and Vitrina 

 pellucida in the woods. Then again. Helix fused, which in some 

 parts of Wales is extremely abundant, did not fall to my lot. 

 Possibly they, or some of them, will reward the research of a more 

 experienced collector. I now give the detailed list : — 



J.C, iv., July, 1884. 



