A GAKDEN SNAIL SHELL. 57 



additional membranous and calcareous matter is exuded, which adheres 

 to the shell edge, or mouth, and hardens into an additional diagonal line of 

 thatch. The colouring deepens, and gradually becomes more pronounced, 

 as line upon hue is added daily. It is bound or strapped on the back of the 

 snail by two muscles which begin at the pillar, and, having penetrated the 

 body below the spiral part, trend forward under the stomach. The fibres 

 having interlaced the "foot" muscles, on their contraction, the body of 

 the Helix is drawn within. The motion may be likened to the 

 shutting up of a lady's flounced parasol, the whalebone ribs repre- 

 senting the muscles. Egress is facilitated by circular fibres which 

 surround the body, above the foot, and this motion is aided by the polished 

 surface of the interior, which is formed by an excretion of pure lime. 

 An old shell has a highly-polished lining, from the constant friction of 

 the soft body passing in and out. 



When about a month old, the snail begins, for some practical end, to be 

 prettily ornamented with the tattoo of his species ; and by this time the 

 glands on the neck of his mantle are well furnished with the mucous slime 

 and the colours which pervade the pores of the shell and vivify it. If you 

 look at any empty garden snail shell, you observe that the upper two out 

 of his three whorls have no tattoo marks ; they are of a pale, horny hue. 

 That important organ, the liver, has not up to that period developed 

 into the fat and plump liver which marks a well fed, pluralist snail. 

 Probably, with an increased power in the odontophore, or teeth- cushion- 

 saw, strong flavoured and thicker vegetation is attacked and digested, and 

 thus the exudations are of more marked and decided tints than before. 

 What we may term the pattern is produced by the admixture of the 

 albuminous or white mucous with the dark-brown excretions from the 

 larger glands of the collar. The process is exemplified in the mechanical 

 arts in the " marbling" of the bookbinder, where different coloured 

 pigments are adjusted in a trough and interspersed, and, as the mechanic 

 is so disposed, either a Scotch plaid pattern or a simple mottle is produced 

 when the book-edges are dipped therein and dried. There is no 

 perceptible growth in the tattoo marks after their first formation — that 

 is to say, no expansion has been traced. 



The power of repairing the shell is worth noticing. In a human 

 habitation, if a roof-tile is broken off, one or two artificers, one 

 or more ladders, and one or two days are employed to repair the 

 damage ; but when Helix aspersa sustains a fracture or damage in his 

 roof, a nerve telegram is sent from the surface of his mantle to the cerebral 

 ganglia or principal nerve centre, and an order is transmitted simul- 

 taneously to the nearest mucous glands in the collar (the thickest part of 

 the body nearest the shell) to exude the necessary cement. This hardens 

 quickly, being a coagulating cement, free from animal matter. 



Eyesight, in our conception of the word, the snail can hardly be said to 

 possess, and so the creature repairs the roof without " surveying" the 

 damaged spot, or overlooking the process of reparation, except by the local 

 sensation of comfort or discomfort. For whether the ocelli or black 

 spots in the posterior or hinder pair of horns are eyes is a moot question. 



