CONTENTS Introduction............... 3 Systematic survey of the Limacidae of the central and western Canary Islands 5 Biogeographical notes on the Limacidae of the Canary Islands . . . . 21 Alphabetical list of the persons who collected or observed Limacidae in the Canary Islands.............. 31 Literature............... 32 INTRODUCTION In the spring of 1947 I was so fortunate as to join for some 9 weeks the Danish Zoological Expedition to the Canary Islands. During my stay I collected materials for the Rijksmuseum van Natuurlijke Historie at Leiden, paying special attention to the land- and freshwater Mollusca. This paper contains the first results of the examination of the Mollusca collected. My Danish friends Dr. Gunnar Thorson and Dr. Helge Volsøe generously put at my disposal the non-marine Mollusca they collected during their stay in the Canaries. When the material has been worked up, duplicates will be deposited in the Zoological Museum at Copenhagen. I am indebted to several persons who helped me in various ways in the investigations here published. Prof. Dr. N. Hj. Odhner (Stockholm) very kindly put at my disposal a MS list of all the Mollusca of the Canary Islands and their distribution, which he had compiled for private use. Mr. Hugh Watson (Cambridge) never failed to help me by examining or lending specimens, and in detailed letters gave me the benefit of his great experience. During my stay in Paris in March 1950 Dr. G. Ranson and Dr. A. Franc put at my disposal for examination the Canarian slugs present in the Muséum