MR. COCKERELL, in his article in NATURE of May 26 (p. 76), draws attention to a list of land and freshwater shells peculiar to the British Islands in Dr. Wallace's new edition of ``Island Life.'' This work is of such very great importance to every one engaged in the study of the geographical distribution of animals, that it is regrettable the author should have repeated an error made in the first edition. Geomalacus maculosus, as is mentioned in Mr. Cockerell's article, is not peculiar to the British Islands. A specimen was discovered in Northern Spain as far back as 1868 by Mr. von Heyden, and recorded in the Nachrichtsbiatt d. deutschen Malakozool. Gesellschaft by Heynemann in 1869. The allied species, supposed to have been found in France, has been proved to be an Arion; but several species of the interesting genus Geomalacus have been recently described by Simroth from Portugal.