ON BRITISH PULMONIFEROUS MOI.LUSCA. 143 



to the United States and to the West Indies. The allies of 

 Helix variabilis are extensively distributed. Helix variabilis 

 itself is found through most parts of Europe, the Mediterranean 

 countries, and the United States of America; and Helix pisana 

 has an equally extensive range. The hispid Helices are gene- 

 rally distributed through Europe. Much confusion, however, 

 exists in lists as regards the immediate allies of Helix hispida. 

 The Helicogenae of Ferussac have great ranges. The com- 

 mon snail of our gardens, Helix aspersa, is equally common in 

 the gardens of Southern Europe, and is found also in parts of 

 Asia, Africa, and North and South America, Helix hortensis, 

 nemoralis and arbustorum, inhabit most parts of Europe ; and 

 Helix pomatia has nearly as great a range as Helix aspersa. 



Bulimus montanus, with us an inhabitant of the plain di- 

 stricts of southern England, on the Continent inhabits subalpine 

 districts, chiefly where limestone prevails. Our Bulimus ob- 

 scuriis is found throughout Europe. Bulimus acutiis, with us 

 usually an inhabitant of the sea-side, is found inland in Switzer- 

 land. On the shores of the Mediterranean it abounds, and 

 assumes many variations of form and colour, along with its 

 near ally Helix conoideus, near which it should probably be 

 placed, rather than with the Bulimi. Both our Achatinas 

 are natives of most parts of Europe, and the A. acicula is 

 found in Northern Africa. As we approach the tropics the 

 forms of this genus multiply. Our species belong to the sec- 

 tion Cionella (Jeffreys), the centre of which may be regarded 

 as placed in the islands of the north-west coast of Africa. 

 Azeca Matoni is a native of Central Europe as well as of Bri- 

 tain. The number of British species of Clausilia is but a 

 small proportion of this large and interesting genus, the varied 

 forms of which abound in the countries of Eastern Europe 

 and the neighbouring parts of Asia. One of our native forms, 

 however, the Clausilia Rolphii of Leach, is confined to Bri- 

 tain, and with us is only found in the south-east of England. 

 Our other species are found in most of the countries of the 

 Continent. The Balea fragilis is frequent in Northern and 

 Central Europe, and is the only European species. Other 

 forms of the genus occur in the West Indian Islands. The 

 genus Pupa affects mountainous districts, and species abound 

 in the Alps, where we find many eccentric and abnormal forms 

 of the genus. France, Russia, and Austria exceed us in the 

 number of species, France doubling our number. One of our 

 Pupae, the Pupa anglica, has never been found out of the 

 British Islands ; the others are generally distributed through 

 Europe, and the Pupa umbilicata inhabits Mount Atlas. 



