THE PHILirriNuS AN INSTANCE. 



distinct species occur which can be included in these genera. 

 Thus three species found in Borneo belong to the genus Cocklo- 

 styfa (antiqua, sulcocincta, and xantJiostoma). CUoraa (see 

 tig. 73, b c) is entirely confined to the Philippines, and is not 

 found even in Mindanao ; Helicarion also is a purely Philippine 

 genus, and its nearest allies even do not occur in India, as might 

 be expected from Wallace, but in the Australian region ; of the 

 genus Obbina four species belong to the Australian province 

 and one to Borneo ; Rhysota is confined to the Philippines. 

 Associated with these peculiar forms are other genera which 

 are not characteristic of these islands, and which have a very 

 remarkable geographical distribution. Closely related to Chlo- 

 rcea in anatomical structure, though not in the appearance of 



FIG. 74. Amphidromiu maevli/erut, Sow. 



the shell is the widely diffused gro\ip of Helix similarit, which 

 is very common throughout the China region ; three or four 

 species occur in the north of Luzon, and only one extends as far 

 south as Bohol ; none at all are found in Mindanao. The only 

 Philippine species of the genus Clausilia inhabits the island of 

 Camiguin to the north of Luzon; it belongs to a Chinese divi- 

 sion of this widely distributed and highly variable family. 

 CJilorrra. itself is most extensively developed in the north of 

 Luzon. Thus these three genera give to the fauna of the north- 

 ern Philippines a sprinkling, as I may say, of the Chinese. 



At the extreme south, on the other hand, there is a certain 

 harmony with the fauna of the Moluccas and the Malayan 

 peninsula. For instance, the genus Amphi<lromv.s, which is so 

 characteristic of the Malayan province (see fig. 74), sends only 



