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92 HYALINIA RADIATULA. 
In Cambridge, it is reported from a Lacustrine deposit of Romano- 
British age at Harlton. 
In West Gloucester, Mr. Kennard reports it from the pre-Roman peat 
deposits at Westbury-on-Severn. 
In Scotland, it is reported from an early Lacustrine bed at Elie, Fifeshire. 
In Ireland, Mr. 8. A. Stewart detected this species in the raised beach 
at Portrush, co. Antrim. Mr. A. W. Stelfox found it in the fossiliferous 
beds at Dogs’ Bay, West Galway, and Mr. J. G. Milne in the deposits on 
the “ Warren,” Achill Island, West Mayo. It has also been found in 
the early alluvial deposits of the Shannon at Limerick, and from buried 
land surfaces of Neolithic age at T'ranarossan and Rosapenna in co. Donegal. 
In Germany, it is recorded from the tufaceous beds of Grenssen, near 
Sonderhausen, in Schwarzbure. 
In France, it is recorded by von Ihering from the tufa of Ober- 
Zaunsbach, French Switzerland, and by M. Fagot with Z. swbradiatulus 
from the quaternary grey clays of Hers, in Haute Garonne. 
In Denmark, it is reported by Mr. Kennard from the Isle of Bornholm. 
In the United States, Mr. Billups records ‘‘ Vitrea hammonis” from the 
old forest bed on Ohio and Great Miami rivers, near Laurenceberg, Indiana, 
and it is also found in the post-glacial deposits of Michigan. 
Variation.—The variability of H. radiatula, especially in the relative 
strength and distinction of the striation, is very considerable, and has 
been the chief basis upon which various forms have been differentiated. 
Mr. G. H. Clapp, of Pittsburgh, who has especially studied the forms 
assumed by this species in America, remarks that in the United States 
there appear to be two somewhat distinct geographical races. 
The northern race shows a narrower umbilicus, with the spiral striation 
only faintly indicated or even quite absent. These are probably the 
true Helix electrina of Gould, being the form found living in Gould’s 
original locality at Cambridge, Massachusetts. It is apparently distri- 
buted over the greater part of Canada, Alaska and the Middle and Northern 
States, but connects with the eastern race by the Virginian examples, 
which approximate to the smoother northern variety. 
The eastern race, which appears to inhabit the coastal plain east of the 
Appalachians, has been noted from New Jersey, Virginia, and district of 
Columbia, passing in the south into Alabama, where it reaches its maxi- 
mum development, shown by the possession of a wider umbilicus and a 
beautiful revolving microscopic sculpture. 
Judging from the distribution of these forms, we may reason that the 
eastern form is the oldest and most primitive, occupying as it does the 
vicinity of the Appalachian region, which harbours the most primitive 
molluscan fauna (excepting only the desert areas), and that the northern 
form is the most modern and vigorous race. 
In Europe, H. petronella would appear to represent the more ancient 
form of H. rudiatula, which by stress of competition now chiefly inhabits 
the mountains, or the inclement regions more or less remote from the 
evolutionary centre. In its stronger spiral strie, wider umbilicus and 
geographical range it bears a similar relation to the typical form that var. 
circumstriata from Alabama bears to the true electrina. 
This spiral or revolving sculpture is variable but yet is generally 
distinguishable in British shells, though they lack the sharp and clear 
definition characteristic of the Alabama specimens. 
