Td 
ss. 
210 GENUS HELIX. 
‘he dentition is of a generalized type, showing little or no tendency to 
the specialization exhibited by certain arboreal and other snails, which, 
by restricting the conditions of life, would debar them from successful 
dispersion. 
Food and Habits.—Vegetation is the staple food of the species of 
the present group, though they are usually not averse to animal food when 
obtainable. Although “essentially crepuscular in habit, they move about 
freely during moist “weather and after or during rain. 
Enemies and Parasites.—'l'he enemies of the present genus are 
very numerous, embracing not only hedgehogs, rats, mice, and other 
mammals, but numerous species of birds also prey upon them, while many 
insects, especially larval Diptera, are very destructive, so that were it not 
that their reproductive powers are so great, it is probable this incessant 
persecution would lead to their extermination ; in fact, the great decrease 
ot Helix hortensis, H. nemoralis, ete., around some of our larger cities has 
been attributed by competent observers to the increase of the numbers of 
thrushes and blackbirds. 
The Parasites also are numerous, but have not received the study they 
merit. ‘he Leptoderw infest the intestinal canal 
and the salivary glands; Gregarinidw are found 
in the kidney; while larval forms of various 
Distomw ave of frequent occurrence in the vis- 
cera; and a minute flagellate infusorian, Bodo | 
helicis Leidy, is said to be found in the copu- pe. a71,—Bodo helicis Leidy 
latory tubes of various Helicide, although their — * 400 (after Saville Kent). 
form suggests the possibility of their being really nenureitones 
Geographical Distribution.—'l'he group is essentially European, 
being dispersed throughout Europe, but it has spread into North Africa, 
Asia Minor, etc. Most of the species are edible, and are much used for 
food by the peoples of Southern Kurope. 
W1G. 272.—Linné's home at Hammarby, near Upsala, now the property of the Swedish Government, 
and used as a Museum to contain a collection of Linnean portraits and numerous relics 
(from photograph kindly supplied by Dr. B. Daydon Jackson), 
