Much more characteristic of South-western Europe, however, than these land-shells are some of the slugs. The peculiar genus _Geomalacus_ is almost entirely confined to Portugal. One species, which I have had several occasions to refer to in illustration of the term "discontinuous distribution," ranges far beyond the confines of that country. This is _Geomalacus maculosus_ (Fig. 18), first discovered in the south-west of Ireland, and more recently also in Portugal. Although careful search has been made for it in other parts of the British Islands, this slug has only been found in the portion of Ireland just indicated. Within the last few years I have taken it, up to a height of over a thousand feet, on the promontory north of the Kenmare River, also from sea-level up to a considerable height near Glengariff, and more recently Messrs. Praeger and Welch discovered it in abundance near the town of Kenmare. But beyond this rather circumscribed area in the counties of Cork and Kerry it does not occur (_vide_ Fig. 19). Several Portuguese species of this interesting genus have since been added to science by Dr. Simroth and others. Dr. Simroth, too, has promulgated the view that the genus _Arion_--to which our common brown garden slug belongs--is of Lusitanian origin. Indeed, the number of species of _Arion_ diminishes as we leave that province, though one extends beyond the borders of Europe into Siberia. The same number of species, viz. five, occur in Germany and in England. _Testacella_--a slug-like mollusc--which lives underground on earthworms, and of which genus three species, viz. _T. maugei_, _T. haliotidea_, _T. scutulum_, are known to inhabit the British Islands, is another Lusitanian animal. All the species are confined to Western Europe and North Africa; they do not even reach Germany or Switzerland. [Illustration: Fig. 19.--Map of the British Islands on which the geographical distribution of _Geomalacus maculosus_ is indicated in black.]