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Show 1892.] THE LAND-MOLLUSCA OF THE PHILIPPINES. 465 Balabac. The mistake about " Palawan passage," alluded to above, has perhaps induced collectors to assign to both sides of the supposed " passage " species that really came from one side only. The only form that appears to have any real authority as coming from Borneo is H. dorice, Dohrn, and I do not feel absolutely certain even about it, while Dohrn himself is very doubtful. But, whether the group be represented in Borneo or not, it is interesting to consider the relationship of these two very isolated groups of Helices, which, it may be remarked, afford very strong evidence for a land connection at some point between Mindoro and the Calamianes. It appears to m e that both of these groups find their nearest relations in an easterly and not in a westerly direction-the Phcenicobius group being nearly akin to the well-known forms mamilla and papilla, from N. Celebes, and these to concisa, Fer., from Waigiou, and quoyi, Desh., from Celebes; the polychroa group to shells of the type of rehsei, Mart., from N . Guinea, and dupuyana, Cpr., from N.E. Australia. It is certain that, as far as these regions are concerned, it is only in N . Guinea and N . Australia that Helices are found of the size and general texture of those under consideration. And it is perhaps worth while pointing out other affinities of the same kind. The remarkable H. antiqua, Ad. & Rve., from N . Borneo, appears closely allied to no other shell but leonardi, Tapp.-Can., from N. Guinea. The unique H. plurizonata, Ad. & Rve., found during the ' Samarang' voyage in Mindanao, is very nearly related to lacteolota, Sm., and agnocheilus, Sm., both from N . Guinea \ The Corasiee of the Philippines are closely related to a group of shells which attain their maximum development in the Solomon Islands. The section of Chloritis which includes such Helices as quieta, Rve., brevidens, Sby., spinosissima, Semp., sauliee, Pfr., sanziana, H. & J., caliginosa, Ad. & Rve., and philippinensis, Semp., has its nearest relations in N . Guinea, Torres Str., and N . Australia. And it is perhaps worth noticing that the Philippine Chlorites just mentioned appear to be restricted to the two islands of Mindanao and Mindoro, i. e. just where the two ridges of connection impinge upon the Philippine group. These facts seem to point to a land connection, no doubt of extreme antiquity, which admitted of Land-Shells of a Papuan and N. Australian type finding their way in a westerly direction. I a m therefore inclined to regard Phcenicobius and the polychroa group, as now occurring in Palawan, Mindoro, and the adjacent islands, as a sort of survival of a fauna which perhaps had once a much more extended range. It is a significant fact that almost the only other Helix from the E. Indies generally which in shape at all approaches the smaller forms of the Phcenicobius group is H. codonodes, Pfr., from the Nicobars. It is possible that eventually fossil or subfossil forms may be discovered in Sumatra and Java which will place this at present isolated form in continuous geographical connection with the apparently related fauna of Busuanga and Mindoro. 1 Had the ' Samarang' been anywhere near N. Guinea, one might have been disposed to believe that the locality for plurizonata was erroneous; its facies is so strongly Papuan. |