252 PROCEEDINGS OF THE MALACOLOaiCAL SOCIEXr. 



I. Clausilia PROPEE. 



In Northern, Western, and Central Europe Clausilia is poorly 

 represented both in sub-sjenera and species, while in South and South- 

 East Europe (Austria-Hungary, the eastern shores of the Adriatic, 

 Italy, the Balkan Peninsula, Greece and the Archipelago, and Asia 

 Minor (the sub-genera are numerous and often handsome, while 

 individual species abound. 



Four hardy sub-genera, Marpessa, Alinda, Cusmicia, Pirostoma, 

 have spread over practically the Avhole of Europe, from Russia to West 

 France and even Portugal, and from Norway to the Mediterranean. 

 On the other hand, the richness of the Clausilia fauna of South-East 

 Europe may be estimated from the following enumeration of the 

 principal sub-genera which find their centre there : Alopia, Triloba, 

 Idyla, Herilla, Delima, Dilataria, Medora, Agathylla, Pseudalinda, 

 Striffillaria, Graciliaria, and others. Albinaria is characteristic of 

 Greece and the islands, Papillifera inhabits South Europe, especially 

 the coast lands, Siciliaria is peculiar to Sicily. 



Within the European region there are four well-marked centres of 

 Clausilian development, quite distinct from one another, and all lying 

 to the south or south-east. It is noticeable that three of these are in 

 close proximity to the sea. They are: (1) Dalmatia, (2) Greece and 

 the islands, (3) Transylvania, (4) Asia Minor, Caucasia, and Syria. 

 A very rough estimate gives about 450 species belonging to these four 

 centres, as compared with about 230 species from all the rest of the 

 region. 



One is struck by a fact, which could be illustrated from other groups 

 of Mollusca, and no doubt from other branches of zoology. Outlying 

 species of a sub-genus will be found, which have either penetrated 

 into regions far from its centre of occurrence, daring pioneers, as one 

 might regard them, of a possible future extension of range, or in some 

 cases relics of a once wider but now contracting distribution. Thus 

 corynodes, Held, reaches East France, though Graciliaria finds its 

 metropolis in Eastern Europe; a single Cristataria {stussineri,^ Bttg.) 

 occurs in Thessaly, thougli its metropolis is Syria, and even Asia 

 Minor contains practically no Cristataria. Albitiaria exhibits 

 a remarkable extension both east and west; degregorii, Plat., 

 occurring in Malta, and lopedusre, Calc, in Lampedusa Island, while 

 Jilumna, Pfr., is a solitary Albinaria in Lebanon. An Agathylla 

 (whose metropolis is Dalmatia) is found in Syria, a remarkable 

 record, for Agathylla is not otherwise found east of Herzegovina, 

 except for one doubtful record in Macedonia. A species of Serrulina 

 (collasi, Stur,). a group characteristic of Armenia and Caucasia, has 

 recently been discovered in a cave in Corfu, a clear case of survival, 

 Serrulifia being only found European in the Miocene. The occurrence 

 of a Pseudalinda (dentiailata, Oliv.) in certain of the North Cyclades 

 is illustrative of the same phenomenon ; von Mollendorff regards the 

 species as a Strigillaria. 



Von Mollendorff regards this species as a Carinigera, to be classified with 

 eximia, Mdff., and lophaiichen, Stur. 



