262 rROCEEDINGS OF THK MALACOLOGICAL SOCIETY. 



others. Garnieria, with eleven species, here attains its maximum, 

 and the other cliaracteristic sub-genera of China are well represented, 

 some by forms of remarkable size and beauty. The low-lying 

 districts, drained by tlie Menam and Mekong Kivers, are practically 

 destitute of species, all the liner forms coming from the high ground 

 of Tongking. 



China. — The Claiisiiia fauna of China is among the richest in the 

 Avorld, but is at present only imperfectly known. Certain portions of 

 this vast empire have been worked with something approaching 

 thoroughness, others have been occasionally visited by the collector, 

 wliile others hiive never been visited at all. Under these circum- 

 stances it would be misleading to attempt to come to any conclusions, 

 based upon apparent abundance or scarcity of Chuisilia in any 

 particular province, as compared with any other. Eut we do know 

 enough to state broadly that the provinces watered by the upper and 

 middle Yang Tse Kiang, East Sytschouau, and Hupe (Hubei), with 

 Hunan to the north and Yunnan to the south-west, are exceedingly 

 ricli in Clausilia. Pere Heude (22) in 1882-90 noted no less tlian 

 seventy-one species, sixty-two of which were described as new. 

 Many of these are among the largest and handsomest species of the 

 genus, rivalling, but not surpassing, the giant forms produced by 

 Japan. Since Heude's time great additions have been made to the 

 list, notably by Bavay »& Dautzenberg, by Gredler, Schmacher and 

 O, Boettger, von Mollendorif, Sykes, and others. China is the 

 metropolis of the tine si\xh-g&VL*iVix Euphcedusa, Formosana, Bemiphcedusa, 

 and Macroph(edusa, while Pseudonenia is well represented in the south, 

 and Gartiieria and Oospira reach the southern provinces. At least 

 120 species in all are known. 



In the west and north-west Clausilia becomes relatively scarce. 

 A fine species has recently been described {CI. cookei, Prest.) from 

 South Shensi, but, as von Mollendorif remarks (38), from the rich 

 development of the genus in Hupe and the neighbouring East 

 Sytschouan,it might have been expected that in the well-wooded and 

 mountainous region of West Sytschouan a number of new species 

 would have occurred. This, however, is not the case, and as a matter 

 of fact the distribution of the genus dies out rapidly to the west and 

 north-west. This is a fact of considerable zoogeographic importance. 

 In the genera Cathaica and Buliminus the centre of distribution and 

 richest number of species occur in Upper Amdo, still further west, 

 but they rapidly fall off as we move east and south-east, and in South 

 China die out almost altogether. The opposite is the case with 

 Clausilia, which is strongest in South China; relatively only a few 

 species reach North Sytschouan, none overpass the borders of Gansu, 

 in spite of the fact that Gansu is otherwise very rich in land Mollusca. 



In the colder and less mountainous regions of North-East China, 

 Clausilia appears to be very infrequent. A list of Mollusca from 

 Dschili (capital Pekiu), drawn up by von Mollendorff, contains no 

 Clausilia. 



Three species from Province Moupin, East Tibet, were described 

 many years ago by Deshayes. They have not yet been rediscovered, 



