622 ABOUT SHELLS. 
Helix stigmatica, and its allies, live under stones or among 
dead leaves. They are dull in color, and the most of them 
small in size. H. stigmatica is never found fairly in the 
daylight. Once only, if I rightly remember, I found an in- 
dividual which had just turned the corner of the rock under 
which it lived. Why do they not come out to the light, and 
what do they live upon in their dark retreats? Another 
group, of similar habits, comprises Helix Titanica, H. pulcher- 
rima and others. These have longitudinal lines of bristles, 
or rather stiff hairs, which are quite conspicuous in the young 
shell, but diminish, wear away, or quite disappear with age. 
Shells often cease growing for a time, so far at least as 
relates to their caleareous covering. Their growth is inter- 
rupted during the dry season, and it may also be by an 
` unusually dry time in summer. In banded shells, when the 
growth is resumed, the pattern of their markings is often, 
- perhaps always, changed. The bands may be moved to the 
right or left, or be divided into two, or two may be united, 
or a color may be suppressed, or a new one introduced, or 
any one color may be widened or narrowed. In Helix picta 
Born., the variety of markings is almost innumerable. While 
the animal remained quiescent as a whole, why did not the 
several parts retain their relative positions? The color- 
secreting glands must have changed in position. 
The wide diffusion of some species, and the extremely 
limited area in which others are found, excite in the inquit- 
ing mind a desire to know the causes of this unequal distri- 
bution. Helix regina in several forms is found in the whole 
of the mountain range of the western part of the island. 
Helicina adspersa is another extensively diffused species» 
besides being very variable in size and markings. VU? 
other hand, Cyclostoma foveatum has been found only in on 
locality, at the base of a high projecting cliff, in considerable 
numbers, but all dead; nor is it known where it lives. 
have looked upwards from below, and have climbed to 
top and looked downwards in vain. Not more than two p: 

