144 F. Stoliczka — Notes on terrestrial Mollusca. [No. 2, 



The fauna in general is intimately connected with that of the 

 lower Tenasserim Provinces, Siam and Camboja, and is in the 

 main characteristically Malayan. As regards variety and number 

 of terrestrial Mollusca, these provinces are well known to range 

 among the richest of the Malayan regions. The interest of this 

 fauna is besides considerably increased by the many peculiar forms 

 it possesses of its own, and which do not appear to occur in other 

 parts of the great Malayan Zoological province. I only need to 

 allude to genera like Pollicaria ( — Hyhocystis), Baphaulics, CIos- 

 tophis, JSophina, Sesara, &fc. The explanation of this peculiarity must 

 probably be sought in the physical condition of the country. 

 Iudeed, it would seem that scarcely anywhere could more favour- 

 able conditions for the development of small local faunas be found, 

 than exist in the neighbourhood of Moulmein. 



Almost all round this place the country consists of isolated hills, 

 or short ranges of hills, composed of sandstones or shales, or more 

 commonly of limestone rock. Many of these hills rise up to eleva- 

 tions of from 2000 to 3000 feet above the level of the sea, and are 

 separated by low land which, for a large portion of the year, is under 

 water. The rocks in question, forming the hills, mostly appear to 

 belong to palaeozoic (chiefly carboniferous) formations, and it 

 seems probable that for a long period the country was not affected 

 by any very considerable change in the level. On the other hand, 

 it can scarcely be doubted, that at no very distant geological period 

 those hills represented as many isolated islands in an extensive bay, 

 a physical condition similar to that of the present Mergui Archi- 

 pelago. The shallow waters between the hills were only gradu- 

 ally reclaimed to dry land by alluvia derived from the more elevated 

 surrounding country. Whatever progress these conditions may 

 have attained, it appears tolerably certain, that the isolation of the 

 hills must have existed during a considerable length of time, and 

 there is also no apparent reason for believing, that the fauna, exist- 

 ing on these hills, had been much affected by any particularly de- 

 structive agencies ; moreover the insular conditions must have been 

 rather favourable to animal and vegetable life. 



All these circumstances tend to shew that the fauna of these hills 

 has existed for a long period, and that at the same time the pro- 



