18 BRITISH MOLLUSKS. 



This and the following species, constituting the subgenus Milax 

 of Gray, Amalia of Moquin-Tandon, are distinguished from the 

 other Limaces by two very obvious characters. The back of the 

 creature is conspicuously keeled throughout its entire length, and 

 the shield is finely granulated, Hke that of Arion, while it encloses 

 merely an irregular calcareous button, for it can scarcely be cabled 

 a shell, which is sometimes flat and partially membranaceous, some- 

 times rudely thickened and convex. The general colour of the body 

 of L. Sowerbyi, which is linearly grooved, is a tawny-yellow, 

 faintly tessellated with dusky brown, and the keel, which stands erect 

 upon the back, especially when the animal is in a state of rest as 

 represented in our vignette, is a pale bright amber. The head is ash- 

 grey with the usual dark lines upon the neck, and the tentacles are 

 of a dull livid blue. The shield is of a moderate size, almost short 

 in comparison with that of L. gagates, being rather abruptly widened 

 and truncated behind. 



Limax Sowerbyi is not uncommon in gardens and shady places 

 in the neighbourhood of London, and some other cities. The spe- 

 cimen from which our figure is drawn was taken by the artist, Mr. 

 Jewitt, in the neighbourhood of Hampstead. Dr. Gray mentions 

 that Hke many of its congeners, it will feed on animal food and even 

 devour the dead remains of an individual of its own species, leaving 

 only the skin of the back. 



Mr. Jeffreys refers this species to Miiller's Limax marginatus. 

 Draparnaud, it is true, has acted on that opinion, but only in doubt. 

 It is, as correctly indicated by Forbes and Hanley, the L. marginatus 

 of Draparnaud but not of Muller. The true L. marginatus of Muller, 

 it can hardly be doubted, is the slug described by M. Bouchard 

 Chantereaux as L. arborum. It cannot be supposed that L. arborum 

 was not known until he collected it in comparative plenty in 1838, 

 in the neighbourhood of Calais. M. Bouchard Chantereaux named 

 it after its habit of living on trees. Mr. Clarke, who collected it 

 abundantly in Ireland, and has figured it in different stages of 

 growth, says " I have seldom found this slug elsewhere than on 

 trees." Muller, when describing the habits of his L. marginatus, 

 says, " In Fago, vulgaris," and dwells particularly on the dark 

 loop band which is characteristic of the species, " cinereus clypeo 

 iitrinque striga obscura. Striga clypei in omnibus nota constans. 

 Juniores et adulti iisdem coloribus," — as shown in Mr. Clarke's 

 figures. 



