38 PROCEEDINGS COTTESWOLD CLUB I90I 
European species is also known from Algiers, and it 
ranges as far east as Turkestan. Its geological range is 
identical with the last-named species. 
Planorbis marginatus, Drap. Twelve examples. Com- 
mon with us at the present day, it is equally so on the 
continent, whilst it is known from Siberia, Turkestan, and 
Algiers. It is found in the Butleyan and Icenian, and has 
been recorded from the lower Pliocene of France (Molasse 
d’eau douce du Lyonnais et du Dauphiné). 
Planorbis spirorbis, Mill. Five examples. The species 
is known from the Butleyan and Icenian, though on the 
Continent its earliest record is from the middle Pleistocene 
of Cannstadt, Weimar. It is a common European form, 
extending into South-West Siberia and Algiers. 
Planorbis contortus (Linn.) Common. This form is 
nearly confined to Europe, occurring elsewhere only in 
South-West Siberia. It is not known from any deposit 
earlier than the Cromerian (Forest Bed), though in 
beds of later age it is common. 
Physa fontinalis (Linn). One example. This species 
ranges through Europe, North America and Siberia. It 
is known from the Cromerian, but in later Pleistocene 
beds it is only recorded from Clacton, Cambridge, and 
West Wittering, though found at several localities in the 
Holocene. 
Physa hypnorum (Linn.) Four examples. This species 
has a wider distribution than the last, occurring as far 
south as Spain. It is known from several Pleistocene and 
Holocene beds. 
Bithynia tentaculata (Linn.) (Common. The earliest 
record for this species in this country is the Icenian of 
Bramerton, though on the Continent it is known from the 
Lower Pliocene (Cozgevza-beds) of Bruchstiick and from 
the Middle Pliocene of Hauterive, France. It is found 
throughout Europe and Siberia, and occurs as far south 
as Spain and Algiers. 
