60. During the year the Director of the National Museum, Singapore, 
found a thriving colony of Amphidromus inversus (Muller) on the trees by 
the potting yard. This is a snail known to occur in the Riau Islands and 
but dubiously reported from Malaya in a single record of many years ago. 
This is certainly the first record of it in Singapore. The size of the colony 
found shows that the snail is established and is able to reproduce itself. 
There is no indication so far, that the snail is troublesome, but till its habits 
are better known it will have to be watched. In appearance the shell is not 
unlike that of the Giant African snail ( Achatina fulica) but it has a reflexed 
rim to the opening by which it can at once be distinguished. 
XX. HORTICULTURAL EXCHANGE 
61. Seed and plant exchange with other botanical organisations in 
Singapore. Malaya and overseas was again an important aspect of the work 
of the Horticultural Division. Two persons were engaged full time on seed 
and plant collection in fulfilment of requests. This work is done on a mutual 
exchange basis and our output is requited by receipts in response to our 
own requests. Material was sent to 159 addresses in 43 countries and received 
from 114 addresses in 39 countries, which are listed in Appendices Vr and 
VII. 
XXI ISTANA NEGARA DOMAIN 
62. Supervision of work at the Domain has not been easy owing to 
the transfer of the Junior Horticultural Assistant and the retirement on medi- 
cal grounds of the Foreman Gardener. The latter post was filled in July. 
In May the post of Horticultural Assistant on the Gardens establishment 
was filled and this officer was placed in charge of the horticultural work 
of the Domain. 
63. The grounds, including the immediate gardens of all the houses 
in the Domain, have been kept in good condition. The three Dennis motor 
mowers gave excellent service on the lawns, and so did the motor scythes 
in the outlying rougher areas. Outdoor receptions, especially in the garden 
of ‘Sri Temasek’ raised a problem of ant control, for the lawns there are 
infested with a small viciously -biting ant. Heavy dosing with an insecticide 
just before a reception would give very brief control. The outbreak of Ele- 
phantopus scaber recorded in last year’s report (paragraph 72) has been 
checked. The use of a selective weed killer was found to be not only expensive 
but not efficient enough. Hand weeding has the plant under control, but as 
the seeds are wind-distributed and the plant is ubiquitous in Singapore, con- 
stant patrolling is necessary. A number of old trees were pruned or removed 
for safety. New plantings were restricted because of the severe drought. Pre- 
paration of compost was again a major item of work and the quantity of 
vegetable debris from the Domain was inadequate for the amount of com- 
post required. Spent hops from a local brewery were a welcome addition 
to the compost heaps. The potting yard has maintained a stock of some 
2,000 potted plants for use as house decoration, not only in the lstana. 
but in the other houses within the Domain, and also for use as bedding-out 
material. Additional orchid beds were planted. 
64. The Domain grounds were open to the public on New Year’s Day 
(January 1st), Chinese New Year’s Day (February 15th), Hari Raya Puasa 
(March 18th) and on Labour Day (May 1st). 
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