NOVEMBER 277 



are shell-fanciers, of course, but theirs is not a serious 

 science. They pay prodigious prices to fill gaps in their 

 collections; 42 was paid recently for a single shell of 

 Gonus gloria-mar is, and a like sum for Cyprea guttata ; 

 but of the strange inhabitants of these pretty tabernacles 

 they reck little and know nothing. Yet even slugs are 

 entitled to such consideration as is due to a family of 

 so high an antiquity as to cause backbones to appear 

 a mere afterthought. The Cambrian beds oldest of 

 stratified rocks reveal about four hundred distinct 

 species of mollusc. 



It must be confessed that British land molluscs do not 

 possess a captivating exterior. Their shells, when they 

 have any, exhibit little of the fantastic or exquisite 

 colour and form bestowed upon those of their marine 

 congeners. Having but a single foot, huge in proportion 

 to the entire creature, and placed, without the luxury of 

 a leg, upon what ladies' tailors euphemistically call the 

 'lower chest,' locomotion can only be performed by a 

 sliding motion, and such sliding is only rendered possible 

 by the profuse secretion of mucus, whereby the animal's 

 path is lubricated. Even so, speed is not a strong point 

 in land molluscs. It has been calculated that the 

 common British garden snail (Helix aspersa) can ' sprint ' 

 at the rate of one mile in about sixteen days and fourteen 

 hours. 



On the other hand, the strength of those humble 

 creatures is amazing. It is recorded of an individual 

 of the species last mentioned, weighing a quarter of an 

 ounce, that it dragged up a vertical surface a weight 

 nine times greater than its own. Another, weighing a 

 third of an ounce, dragged along a smooth table a load 



