A NEW DEROCERAS SPECIES FROM NORTH-WESTERN SPAIN (GASTROPODA: PULMONATA: AGRIOLIMACIDAE) by

Deroceras ercinae spec. nov. is described from the Cantabrian Mountains, Spain. The charac-ters used to define the subgenera of Deroceras are discussed. It is demonstrated that the present subdivision of this genus into subgenera is not based on synapomorphic characters. A. J. de Winter, Dorpsstraat 139, 6871 A G Renkum, The Netherlands. In April 1984 some slugs belonging to the genus Deroceras Rafinesque, 1820 were collected around the Lago de la Ercina in the Picos de Europa, province of Oviedo, Spain. They could not be identified with any known spe-cies. Therefore, these slugs are here described as belonging to a new species. Al l measurements have been taken from specimens preserved in 70 % eth-anol, after drowning in water