4 SCHARFF : DISTRIBUTION OF BRITISH L. AND F. MOLLUSCA. 



The second district is characterized by the presence of a number 

 of Germanic forms, such as Helix obvoluta, H. carthusianella, 

 ( = H. carthusiana), Clausilia ventricosa ( = CI. biplicata), CI. Rolphii 

 and Bulimus montanus ( = Buliminiis montanus). Here we have, no 

 doubt, a well-marked province. 



Prof. Forbes' third district includes the south-west of England, 

 with such characteristic forms as Helix pisana and Bulimus acutus 

 ( = H . acuta). The former has since been found in south Wales, 

 and the latter occurs also in the Channel Isles, the Isle of Man, 

 Cheshire, and some of the islands on the west coast of Scotland. 

 Its claim to form a separate province therefore falls to the ground, 

 but it might be conveniently united with the Channel Isles and south 

 Wales, with which it has the following in common, which are absent 

 from the second district, viz., Testacella maugei, Helix pisana, and 

 H. acuta. 



The fourth district, viz., the north-east of England, has not any 

 peculiar species, but, according to Prof. Forbes, it contains such 

 forms as Helix scarburgensis ( = H. lamellata), Helix excavata 

 ( = Hyalinia excavata), and Pupa anglica, unknown in the south. 

 However, as we now know, H lamellata occurs also in Ireland and 

 Scotland, Hyalinia excavata in the south-west of England, in the 

 west of Ireland, and on the island of Arran in Scotland ; while 

 Pupa anglica appears in the Channel Isles, Herefordshire, m 

 most parts of Ireland, and in the extreme north of Scotland. 

 In fact, this is a province which, I think, might be more 

 correctly united with the second, with which it has many forms in 

 common. 



The North-west of England, with the Isle of Man, forms the 

 fifth district, but it does not contain any peculiar forms either, and 

 should be included in the preceding. 



The sixth and seventh districts are the North and South of 

 Ireland. The former has no peculiar species, and only three — as far 

 as I am aware, viz., Helix pisana, H. arbustorum, and Clausilia 

 laminata — which are not also found in the South. The South, on 

 the other hand, has five species which have not hitherto been dis- 

 covered in the North, viz., Testacella maugei, Geomalacus maculosus, 

 Succinea oblonga, Planorbis corneus and Limnaia involuta. Not a 

 single one of the peculiar Germanic forms referred to in the second 

 district penetrate into Ireland. 



The districts VIII., IX., and X. include the South and North 

 of Scotland and the Shetland Isles respectively. The South of 

 Scotland, according to Prof. Forbes, is distinguished from district IX, 

 the North of Scotland, by the absence of Pupa cylindrica (= umbili- 



