into a work like the prefent. The genus however is in 

 reality of very great importance, fince it Hands, as it 

 were, the general archetype or pattern on which the 

 animals of almoft all the univalve (hells are formed : 

 indeed fo very nearly are fome of them allied to this 

 genus, that they feem, on a curfory view, to differ in 

 fcarce any other circuniftance than that of being fur- 

 nifhed with iheils, into which they can at pleafure 

 withdraw themfelves. Of this the genus Helix, which 

 contains the common or fhell-fnails, is a convincing 

 proof. The reft of the univalves, (with a few remark- 

 able exceptions,) are more or lefs fimilar to the genus 

 Limax. Two of the moft familiar fpecies of Limax 

 which this country produces are the Limax ater and 

 maximus : the one is diitinguifhed by its intenfe black- 

 nefs, and is extremely common in fields and meadows ; 

 the other, lefs common than the former, is of a pale 

 brown, with irregular deep-black fpots and flreaks : it 

 is principally feen in woods and in garden-ground du- 

 ring the vernal and autumnal feafons, and not unfre- 

 quently creeps into houfes. Both agree in their mode 

 of living; feeding on the leaves and roots of vegetables. 

 The fpotted Slug, like fome others of its genus, is often 

 infefted by a very fmall fpecies of acarus, 1 which ap- 

 pears in great numbers, running with much celerity 

 over the animal, and frequently entering the lateral 

 foramen of the body. The Limax however, either 

 from its natural hebetude, or from being coated at all 

 times by a quantity of mucus, feems to feel no parti- 

 cular inconvenience from thefe little infects, and {hews 

 no fymptoms of irritation even when they are running 

 in and out of the orifice in its fide. 



