204 
BODY SCULPTURE. 
With the atrophy or redaction of the shell and its predominant 
intlnence as a modifying factor lost, the foot, the body, and the 
mantle are free to develop sncli protective moditications in form, 
colour, textnre or function as may he best adapted to compensate for 
its loss, snch compensation may be by the development of a thicker 
and tougher integument, of a more abundant mncosity, or of colonring 
or markings harmonizing more closely with the nsnal snrronndings of 
the animal ; in marine species, stinging cells, antotomy or voluntary 
amputations of portions of the body, and a great capacity for regenera- 
tion of injured parts may be instanced as some of the compensatory 
attributes that have been accpured. 
The Visceral or Body Region. 
'I'he Body is usually more or less covered by the mantle, and consists 
in the testaceous species of the dorsally projecting, visceral sac and 
the connected cavity above the muscular foot. It varies in shape 
according to the genus and in the xirionidw and Lbnacidw the spirally 
coiled dor.sal region, which characterizes the testaceous Gastropods, 
Diagrammatic sections showing the arrangement of the visceral sac, etc., in the coiled HcUcidte 
and the secondarily symmetrical Lintacid<e (after Hinney). 
Fig. 403. — L'lDia.x. Fig. 404. — Jlciix. b.c. body or visceral cavity ; c. collar of mantle ; r.c. 
respiratory chamber ; sh. shell. 
has become depressed and battened out, so that all external trace of 
its former coiled condition is lost and a secondary external symmetry 
acquired ; the mantle and shell being also reduced iu size, the body 
region is consecpiently permanently exposed and its integument has 
therefore accpiired a thicker and more coriaceous character. 
The surface of the body, though generally thin, soft and flexible, is 
covered, in the terrestrial si)ecies, by more or less closely disi)Osed and 
prominent rugosities, which vary in number and character according 
to the species, the interstices between them serving to distribute over 
the surface of the body the mucus poured forth by the glandular 
integument, but in addition to the local diffusion of the mucus thus 
secured, there are deep and longitudinally disposed grooves, which 
extend from the pallial region to the anterior part of the body, and 
give off during their course many subsidiary and ramifying branches. 
