HELIX HORTENSIS. 361 
Geographical Distribution.— //elix hortensis is one of ow most 
highly organized species and scarcely inferior to its close ally, //. nemorulis. 
Its probable earlier advent and more primitive organization is shown not 
only by its more extensive northern and north-western range and its 
somewhat more local or discontinuous distribution, but by the somewhat 
sacculate structure of the vaginal mucus glands, rec calling that characteristic 
feature of the more ancient Belogona Huadenia’ he gypsobelun or 
love-dart, however, exhibits a considerable and remarkable comple xity, 
closely resembling that of HKuparypha pisana, and quite different in char- 
acter from that of //. nemoralis, which has its relationship with that of 
HT. aspersa, from which it is scarcely distinguishable, except by its size. 
Helix hortensis as probably arisen within the north-westerly part of 
the Germanic region, and has diffused itself chiefly to the north-west, 
spreading to the i aroes, Iceland, and evento North America; its extension 
in other directions being comparatively limited, probably owing to the 
keener competition encountered from the highly organized prior occupants 
of the territory. 
Fic. 403.—Holaretic Distribution of Helix hortensis Miiller. 
ey Recorded Distribution in the Nearectie and Western Palearetic regions. 
Supposed Distribution of Land areas in Tertiary times, based on the 
present shallower ocean areas, and showing the hypothetical land- 
bridge connecting Europe with America. 
Present Distribution of Land areas. 
The presence of //. hortensis in North America is somewhat perplexing, 
and has Jed to much speculation and diversity of opinion as to its claim 
to be regarded as a true native of that country, or whether it owes its 
presence there to the voluntary or involuntary agency of man, as it is a 
species which has extended its range very far beyond that of its immediate 
European allies, from which it is now completely isolated geographically ; 
1 Monog. i., p. 396, f. 727. 
