100 Contributions to Indian Malacology. [No. 2, 
Cataulus. Near the’ periphery, the whorls are more numerous, but 
their boundaries are indistinct. 
I have in this and {other papers, already given all the details con- 
nected with the occurrence of the four species of Diplommatina as yet 
described from Burma. The only known Helicina from Northern 
Burma is also described above. 
Georissa. 
I have described (Ann. and Mag. Nat. Hist. for June 1864) as a 
distinct genus, under this name, the species of Burmese and Khasi 
‘shells referred to Hydrocena by Mr. Benson, both the animal and 
operculum differing from those in that genus. But one species is 
known to exist in Pegu, G. pyxis, Bens., and I have met with that 
in many places west of the Irawady, from Thayet Myo to south of 
Bassein. G. Frustrillum, Bens., I only met with at the original local- 
ity, Mya Leit Doung, Ava. 
It is evident that two very distinct zoological provinces exist in 
Burma, exclusive of Martaban and Tenasserim, which form a third, 
characterized by the appearance of several Malayan generic types, such 
as Raphaulus, Hybocystis and Rhiostoma, and others apparently pecu- 
liar, as Sophina. The two northern provinces are: 1st, Arakan, with 
the southern part of Pegu near the sea, enjoying a very humid climate. 
2nd, Upper Burma, with, in many parts, a very dry climate. The 
boundary in the Irawady valley may be drawn roughly above 
Henzada, although species belonging to each fauna, as is usually the 
case, pass over the border. The first province, besides a considerable 
number of peculiar species, is especially characterized by forms 
common, on the one hand, to the Khasi hills, and even to the Hima- 
layas, and, on the other hand, to Tenasserim. Examples of the first 
are Helix plectostoma, Bens., H. delibrata, Bens., H. castra, Bens., &. 5 
of the second, Cyclophorus awrantiacus, Schum., C. speciosus, Phil., 
Leptopoma aspirans, Bens., Nanina honesta, Gould, &e. In the Ava 
province, on the other hand, the forms which have also been found in 
India are mostly inhabitants of the plains, such as Helxw similaris, 
Fer., Bulimus pullus, Gray, and B. ceenopictus, Hutt. The genus 
Hypselostoma has as yet only been found within this province, or close 
to its borders. It isrich in species of Plectopylis, and in varieties or 
