312 THE NATURAL HISTORY 



" Pannel's hole." Among our Aquatic Univalves 

 common in the Great Pond, we may specify Valvata 

 piscinalis, the shell of which is a quarter of an inch 

 long, of a yellowish horn colour, and having a circular 

 aperture, closed when the animal is at rest, by a shelly 

 operculum. This species is still more plentiful than 

 the Cyclas lacustris. 



Our Slug Family is represented by the Black Slug 

 (Arion ater), the Garden Slug (Arion hortensis), the 

 Large Slug (Limax maximus), the Yellow Slug (Limax 

 flavus], and the Field Slug (Limax agrestis). The two 

 first, as the gardener assures us, have an unpardonable 

 weakness for his plants and fruits, a weakness which. 

 he visits with capital punishment as often as he has 

 an opportunity of doing so ; they also vary their diet 

 with earthworms and other animal matter, living and 

 dead, sometimes even indulging in cannibalism. Arion 

 ater, however, is thought by many persons of easy 

 belief to be endowed with a valuable property, in 

 which may be found a slight compensation for its 

 depredations. In the destruction of warts on the 

 human skin, it has the credit locally of having been 

 eminently successful long before the application of 

 acetic acid to this purpose. The living slug, after 

 having been carefully rubbed over the parts affected, 

 is to be securely impaled on a thorn in some secluded 

 place and there left to die. If, from the commence- 

 ment of this experiment, the warts do not gradually 

 become " fine by degrees and beautifully less," until 

 they finally disappear, the operator has failed in one 

 or other of the two conditions indispensable to success 

 implicit faith or strict secresy ! The Limax maximus 

 and Limax flavus frequent our houses, and assiduously 

 take upon themselves the duties of scavengers during 

 the hours of darkness, retiring to obscure damp places, 

 drains, &c., in the daytime. They are not, however, 

 confined to our buildings, they may be found also 

 under stones in damp situations and in the decaying 



