1891.] 1>. Prain — The Vegetation of the Ooco Group. 299 



lying north-eastern peninsula had originally been detached from the 

 main island and, being an islet of considerable width, that a causeway, 

 ultimately becoming an embankment, has been thrown up by wave-action 

 from each of the two adjacent bays. Soil washed down from the adjacent 

 slopes during the rainy season has in the form of fine silt closed up the 

 porous shingle banks at either end till these can now retain the fresh 

 water within them and prevent the percolation of sea-water from with- 

 out. To the east side of this lake there is a small flat meadow covered 

 with KylUnga and Fimhistylis along with some Oyperus polystachyus but 

 very little grass. Whether this meadow was originally a naturally bare 

 patch or is only part of the clearing made in connection with the 

 abandoned settlement on the adjacent hill it is difficult to say. If, how- 

 ever, it was artificially cleared, it is unlike the rest of the clearing in 

 this, that no woody jungle is reappearing in it now. At the time of our 

 visit a number of snipe frequented the meadow. Close to the edge of 

 the lake is a continuous belt of Hygrophila quadrivalvis ; within this, and 

 extending into the water, is a belt of Polygonum all round the margin of 

 the lake ; inside the Polygomim float large matted patches of Panieum 

 Myurus. Here and there are patches Limnanthemum indicum ; there 

 is also a considerable quantity of Nymphcea rubra. The ordinary white 

 Nymphcea Lotus, so common in similar spots in the Andamans, is not 

 present, a circumstance which inclines one to think that this red water- 

 lily may have possibly been introduced during the attempt to settle in 

 the island. The water is quite potable and apparently wholesome ; 

 neither Ghara nor Zaniohdlia is present, perhaps the water is rather 

 deep for these. 



Very different in many respects is the lagoon on Little Ooco 

 which is simply a mangrove creek that has been banked off from 

 the sea by a small sand-dune having been thrown up across its mouth. 

 It is not more than lf-2 feet deep anywhere, with also a level but at 

 the same time a softer bottom than the Great Coco lake, and this bot- 

 tom is covered uniformly throughout by a meadow of Ohara mixed with 

 ZanichelUa. Here the water, though perhaps potable on an emergency, 

 and though used by native craft that call in for it, is slightly 

 brackish, and the lake is fringed throughout by Bruguiera, Lumnitzera, 

 Ceriops, Avicennia, etc., while clumps of similar mangrove trees occur 

 throughout it. Its area is considerably greater than that of the Great 

 Coco lake, for it is about a quarter of a mile long and a furlong across 

 at the widest part ; it was haunted at the time of our visit by teal. 

 Here, curiously enough, Panieum Myurus does not occur, its place being 

 taken by Paspalum scrohiculatum which floats in great patches at its 

 south-western corner. There is no Limnanthemum and the Nymphcea 

 39 



