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

——chap, x.] THE PAL^ARCTIC REGION. 215Ethiopian districts of Senegal and Gambia to the east.a mingling of theThere istwo faunas, but the preponderance seems tobe undoubtedly with the Palasarctic rather than with theEthiopian. I owe to Mr. E. B. Sharpe of the British Museum,a MS. list of the birds of these islands, twenty-three species inall. Of these eight are of wide distribution and may be neglected.Seven are undoubted Palasarctic species, viz. :Milvusictinus, Sylvia atricapilla, S. conspicillata, Corvus corone, Passersalicarius, Certhilauda desertorum, Columba livia. Three arepeculiar species, but of Palasarctic genera and affinities, viz. :Calamoherpe brevipennis, Ammomanes cinctura, and Passer jagoensis.Against this we have to set two West African species,Estrilda cinerea and Namida meleagris, both of which wereprobably introduced by man ; and three which are of Ethiopiangenera and affinities, viz.:—Halcyon erythrorhyncha, closelyallied to H. semAcceruka of Arabia and North-east Africa, andtherefore almost Palasarctic; Accipiter melanoleucus ; an&Pyrrhulaudanigriceps, an Ethiopian form ;but the same species occursin the Canaries.The Coleoptera of these islands have been also collected byMr. Wollaston, and he finds that they have generally the sameEuropean character as those of the Canaries and Madeira, severalof the peculiar Atlantic genera, such as Acalles and Hegdcr,occurring, while others are represented by new but closely alliedgenera.Out of 275 species 91 were found also in the Canariesand 81 in the Madeiran group ; a wonderful amount of similaritywhen we consider the distance and isolation of these islandsand their great diversity of climate and vegetation.This connection of the four groups of Atlantic islands nowreferred to, receives further support from the occurrence of landshellsof the subgenus Leptaxis in all the groups, as well as inMajorca ;and by another subgenus, Hemicycla, being common tothe Canaries and Cape Verd islands. Combining these severalclasses of facts, we seem justified in extending the Mediterraneansub-region to include the Cape Verd Islands.