104 MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 
Agriolimax agrestis (L.). 
Alie parve, ut que gregatim folia sectantur, et hortos infestant cinerei aut fusei 
coloris Gesner, de Aquatil. lib, 4, pp. 254 et 256. 
Limax cinereus parvus, immaculatus, pratensis Lister, Hist. Anim. Angl., 1678, 
p. 130, tab. 2, f. 16. 
Limaz cinereus tmmaculatus L., Fauna Suec., 1746, p. 366, No. 1279. 
1758 Limaz agrestis L., Syst. Nat., ed. x., i., p. 652. 
1774. — vreticulatus Miller, Verm. Hist., ii., p. 8, No. 207. 
1819 — Obilobatus Fér., Hist. Moll., p. 74, pl. 5, f. 11. 
1841 — _ tunicata Gould, Invert. Massachusetts, p. 3. 
1848 — pallidus Schrenk, Land u. Sussw. Livlands. 
1855 — (Kulimaz) agrestis Moq.-Tand., ii., p. 22, pl. 2, f. 18-22, and pl 3, f. 1, 2. 
1861 — _ veranyanus Bourg., Spicil. Malae., p. 30, pl. 13, f. 9. 
1862 — heydeni Heynemann, Mal. Bl., p. 210. 
1870 — norvegicus Westl., Fauna Moll. Suec., p. 22. 
1874. — (Agriolimax) fedtschenkot Koch & Heynemann, J.D.M.G., p. 153. 
1815 Limacella obliqua Brard, Coq. Paris, p. 118, pl. 4, ff. 5, 6, 13, 14, 15. 
1868 Agriolimax agrestis Malm, Skand. Limac., p. 69, pl. 3, f. 8. 
- 1882 — panormitanus Less. & Poll., Monog. Limac. Ital., p. 52, pl. 1, f. 5. 
b, ISTORY. — Agriolimax agrestis (agrestis, 
inhabiting fields) is one of the commonest 
and most destructive of our native species, 
and was noticed and discriminated by some 
of the earliest writers. 
It was first added to the British lists by 
Martin Lister in 1674, who distinguished it 
from other kinds by its smaller size and its 
peculiar milky-white mucus. 
It is the most highly organized of the 
genus, and owing to its marvellous powers 
of adaptation and its habit of frequenting 
cultivated land, it has been transported to 
almost every land where the white man has 
established himself, thriving under its new 
surroundings to the prejudice of the abori- 
ginal species. 
According to Mr. C. 'T’. Musson, Limaax 
molestus Hutton and LZ. legrundi Tate are 
both referable to our Agriolimax agrestis, 
cee. D- A. Cockerelf_ while Luther considers LZ. heydent Heyne- 
mann as another synonym of the same 
species. The Limaa weinlandi of Heynemann has also been regarded as 
merely another form of this widely-dispersed slug. 
With this species Prof. I. D. A. Cockerell, F.Z.8., of Las Cruces, New 
Mexico, U.S.A., has been associated in recognition of his valuable labours 
in the elucidation of the variation and affinities of the present and other 
species. 
Diagnosis.—ExTERNALLY, A. agrestis may be distinguished from its 
congeners by its pale ochreous or whitish body colour, sometimes spotted or 
blotched with darker pigment, but more especially by its milky-white slime. 
INTERNALLY, it is sharply separated from all other British slugs by the 
bulky penis-sheath, and the variously digitate claw-like flagellum at its 
distal extremity. 
