The geographical distribution of animals, with a study of the relations ...

—198 ZOOLOGICAL GEOGRAPHY. [part hi.insularity, have sufficed to commence the work of specificmodification.There are also a few small land-shells and severalinsects not yet found elsewhere than in Britain ;of the smaller Mammalia—a shrew (Sorcx rusticus).and even oneThese factsare all readily explained by the former union of these islandswith the Continent, and the alternate depressions and elevationswhich are proved by geological evidence to have occurred, bywhich they have been more than once separated and unitedagain in recent times. For the evidence of this elevation anddepression, the reader may consult Sir Charles Lyell's Antiquityof Man.Iceland is the only other island of importance belonging tothis sub-region, and it contrasts strongly with Great Britain,both in its Arctic climate and oceanic position. It is situatedjust south of the Arctic circle and considerably nearer Greenlandthan Europe, yet its productions are almost wholly European.The only indigenous land mammalia are the Arctic fox (Canislagopus), and the polar bear as an occasional visitant, with amouse {Mus islandicus), said to be of a peculiar species. Fourspecies of seals visit its shores. The birds are more interesting.According to Professor Newton, ninety-five species have beenobserved ; but many of these are mere stragglers. There aretwenty-three land, and seventy-two aquatic birds and waders.Four or five are peculiar species, though very closely related toothers inhabiting Scandinavia or Greenland. Only two orthree species are more nearly related to Greenland birds than tothose of Northern Europe, so that the Palrearctic character ofthe fauna is unmistakable. The following lists, compiled froma paper by Professor Newton, may be interesting as showingmore exactly the character of Icelandic ornithology.1. Peculiar species. — Troglodytes borealis (closely alliedto the common wren, found also in the Faroe Islands) ; Falcoislandicus (closely allied to F. gyrfalco) ;Lagopus islandorum(closely allied to L. rupestris of Greenland).2. European species resident in Iceland.Emberiza nivalis,Corvus corax, Haliazctus albicilla, Rallus aquaticus, Hamiatopusostralegus, Cygnus fcrus, Mcrgus (two species), Phalacocorax (two