100 THEBA CARTUSIANA. 
whose bulk is so strikingly greater ; each batch is composed of from 40-80 
eggs, which hatch in about a fortnight, and become adult towards the end 
of their first year. ‘lhe shell when immature is said to be hispid, thin, and 
transparent, but gradually thickens, becomes more opaque, and the hairy 
investment lost as growth proceeds, the aperture being completed when 
full size is attained. 
Habits and Habitat. — Although Moquin-T'andon describes this 
species as rather slow, the animals studied by me were very bold, active, 
and fearless, carrying the shell somewhat inclined when crawling, and 
capable of travelling two inches in one minute, or at the rate of a mile 
in about twenty-two days. 
Though it may occasionally be found on rushes in marshy places, it 
usually frequents dry and arid, calcareous or sandy ground, clinging to 
the vegetation or to the grass stems, but at Granville, Manche, it was 
observed by Mr. F. H. Sikes to have an especial predilection for the dead 
nettle (Lamium sp.). ‘Though chiefly confined to chalky soil and to the 
vicinity of the sea in this country, it is by no means restricted thereto in 
Europe, being found quite in the centre of the continent and on a variety 
of geological formations and under varied physical conditions, flourishing 
on dry and arid ground, but also prospering on marshy land ; and living 
not only on the plains, but ascending the Pyrenees to a height of 3,000 
feet, and in the Emilian Appenines may attain an altitude of nearly 
3,600 feet. 
During the day it adheres firmly by means of the epiphragm to the stems 
of plants and grasses, or other suitable objects, frequently fully exposed to 
the full influence of the hot summer sun, the closure of the aperture of the 
shell by the epiphragm preventing the evaporation of the natural moisture 
and consequent desiccation of the animal. 
If removed from its position and the epiphragm necessarily broken, the 
animal promptly emerges from its shell, the hind part of the foot being first 
extruded with an energetic jerk, quickly followed by the head and body. 
The heart pulsations would appear to be more active than in Ashfordia 
granulata, as a specimen in August 1894 showed 56 pulsations per minute 
at a temperature of 63° Fahr. 
It appears to dislike strong winds, and this may account for its preference 
for the hollows of the downs, where it is somewhat sheltered from its 
violence, which in exposed places probably dislodges the shell from its 
fixation to the vegetation, and compels resort to concealment, as during 
high winds no shells are to be found in exposed positions, but on still 
days and in sheltered spots the animals remain affixed to the vegetation 
and fully exposed to the sun’s rays. 
No direct observations on the food of this species have been published, 
but it is inferred that the plants frequented are probably fed upon. 
During severe weather the animals bury themselves in the sand or earth, 
and according to the observations of Mr. Hillman apparently resort to 
similar protection against drought, as few or none can be found at such 
times. 
Enemies.—Retowski has recorded that in the Crimea, Russia, this 
species is preyed upon by Phosphuga laevigata, a coleopteron of the family 
Silphide, while Zonites algirus deyours the animal quite to the apex of 
the shell. 
