342 
parviflora forming the interior. On the island of Tarakan there 
is a well developed swamp, the interior of which is mainly 
composed of large trees of Lumnitzera littorea. In swamps which 
cover coral-reefs and are more or less exposed, Sonneratia Pagatpat 
often occupies the outermost and most exposed position. 
General remarks on the utilization of the 
mangroves 
Cutch, 
Cutch was formerly produced from the wood and bark of 
certain Indian Acacias and was used as a dye in printing cotton 
cloth. It was also used as a tanning-extract. It was found that 
a very good dye and tanning extract could be produced from 
certain mangrove-barks with very little trouble and, of recent 
years, this “mangrove-cutch” has occupied a prominent place 
in the trade. The true Indian cutch furnished a brown dye. 
Tn competition with true cutch, the mangrove-barks were at 
a disadvantage because they contained too much red color. 
Since the introduction of aniline dyes, the Bismarck Browns 
have largely supplanted the different kinds of cutch so that, 
at present, the different mangroves are not commercially 
important as sources of dye bark. As the use of cutch tor 
dyeing purposes decreased, its use as a tanning-extract has in- 
creased. The species which are used in preparing mangrove- 
cutch are Rhizophora conjugata and mucronata, Brugiiera gyi- 
_ norrhiza and eriopetala, Ceriops tagal and Roxburghiana, all spe- 
cies of very wide distribution and occurring throughout the 
Malay region. The extraction of the tanning extract has been 
undertaken at the following places in western Borneo: Brunei 
Bay, Santubong and Pontianak and at Kudat and Sandakan 
in north Borneo. Mangrove-bark has been used by the natives 
for dyeing and tanning their fishing nets and lines and the 
sails of small boats since very ancient times. 
The percentage of tannin contained in mangrove-bark is 
high. Various analyses have indicated from 15 to 60°/,. I think 
it may be doubted if this latter figure is correct. Possibly it 
