From the Journal, Asiatic Society of Bengal, Yol. LXII, Part 11, No. 2, 
1893. 
On the Flora of Narcondam and Barren Island.— By D. Prain. 
Plates III and lY. 
[Read May 3rd]. 
§ Introductory Sketch. 
The Indian Ocean is broken on the north by the Indian Peninsula 
into two roughly triangular seas. The eastern, rather the smaller, forms 
an area known vaguely as the Bay, Gulf, or Sea of Bengal—the first 
of these names being that most usually employed—bounded on the west 
by Ceylon and India, on the east by the Malay Isthmus (Tenasserim) 
and Indo-China, and on the north by the Gangetic Delta. The ocean- 
surface thus defined is, however, further differentiated into three distinct 
hydrographical areas. 
These areas are (a) the Bat of Bengal, a bight limited to the west 
by the Kistna Delta, to the east by Cape Negrais and situated to the 
north of an arbitrary line—the parallel of Lat. 16° —beyond which 
it passes into (b) the Sea op Bengal, stretching from Coromandel 
and Ceylon, on the west, to the Andamans and Nicobars on the east. 
The Sea of Bengal opens southwards into the Indian Ocean proper, from 
which it is hydrqgraphically rather definitely limited by the somewhat 
rapid upward shelving of its floor from the bottom of that ocean to a 
uniform depth of 2200 fathoms along a line roughly coincident with 
the parallel of Lat. 6° N. Thereafter its floor is a plain and practically 
253 
