MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 89 
Limax arborum Bouchard-Chantereaux. 
1774 Limax marginatus Miller, Verm. Hist., ii., p. 10, No. 206. 
1779 — _ scopulorum Fabricius, Reise Norwegen, p. 298. 
1822 — cinereus var. B Nilsson, Hist. Moll. Sveciie, p. 7. 
1833 — gagates Boubée, Bull. Hist. Nat. Frane., p. 13. 
1836 — _ salicium Bouillet, Cat. Moll. Auvergne, p. 18. 
18387 — limbatus Held, Isis, p. 303. 
1838 — arborum Bouch.-Chant., Moll. Pas-de-Calais, p. 28. 
1843 — glaucus and arboreus Clarke, Ann. and Mag. N.H., p. 334, pl.11, ff. 4-10. 
1848 = — livonicus Schrenk, Land u. Susswass. Livlands, p. 142. 
1852. — marginatus Baudon, Cat. Moll. Oise, p. 6. 
1852. —_ scandens Normand, Dese. Limac. Nouv., p. 6. 
1856 — _ sylvaticus Goldfuss, Rheinpr., p. 65, pl. 3, f. 8. 
1857 — arboreum Gray, Turton’s Manual, p. 82. 
1870 — _ bettonw Sordelli, Atti Soc. Ital. Sei. Nat., p. 251. 
1871. —_ agrestis var. saxorum Baudon, Mém. Limac. Oise, p. 19, pl, 4, ff 10-12. 
1877 altilis Fischer, Journ. de Conch., p. 49. 
1868 Lehmannia marginata Malm, Skand. Limace., p. 83. 
1876 Amalia marginata Fischer, Journ. de Conch., p. 53. 
18sO) — = marginata var. mongianensis Paulueci, Fauna Mal. Calabria, p. 23. 
ISTORY.—Limae arborum (arborum, belong- 
ing to trees) has attracted the attention of some 
of the earliest observers, and has, therefore, 
received a variety of names, but it was not 
until 1838 when Bouchard-Chantereaux un- 
mistakably described its peculiarities that a 
name was apphed to it with certainty. 
Though it 1s probable that previous authors 
had this slug before them, their descriptions 
are not such as to remove all doubt, and have 
therefore given rise to much controversy, so 
that it has been deemed advisable to adopt 
the first name about which no difference of 
opinion has arisen. 
The Limax marginatus of Miller, the L. 
scopulorum of Fabricius, LZ. sylvestris of Sco- 
poli, LZ. gagates of Boubée, L. salicium of 
Bouillet, and LZ. limbatus of Held, according 
to many of the best authorities, are all prob- 
ably referable to Limaw arborum, but the mar- 
gin of doubt that exists precludes the use of 
any of these names for the species. 
Though classified with LZ. favus mainly on account of the exact similarity 
of their alimentary systems, yet this location is not altogether satisfactory, 
as the sexual organs demonstrate a close relationship with A griolimax, from 
the Caucasian stock of which group Simroth believes this species to have 
been derived, the connecting links being still existent in Abyssinia; L/mav 
arborum therefore connects the Agriolimaces with the typical Limaces, par- 
taking to some extent of the peculiarities of each. 
With this species, so especially identified with the power of spinning 
mucous threads, we have associated Mr. H. Wallis Kew, I'.Z.8., of Hornsey, 
London, who has devoted so much time and ability to the investigation of 
the phenomenon of thread-spinning in mollusks as well as other animals. 
