Planorbis exustus Desh. and Amerianna carinata (Adams) in Java

Planorbis exustus was found in Java by Dr G. BRAS in the neighbourhood of Djakarta. It was reported on by VAN BENTHEM JUTTING (1946, p. 221). In 1947 I collected many specimens of this species in the ponds of the Botanic Gardens at Bogor, Java, and found it also present in the indoor aquaria of that institute. In July 1951 I observed one specimen in a pond of the Hortus of the University of Indonesia, at Bandung, Java, but it has not occurred there since. Evidently it was introduced into the Bandung area with waterplants from Bogor. I have no other records of this invader. In 1951 several specimens of a sinistral shell were brought to me for inspection and identification. The snails were abundant in the aquaria of the Bogor Botanic Gardens. My assistant ASMAN brought me about 50 specimens of the same kind from his home aquarium and told me that similar snails occurred in the tanks of a Chinese professional aquarist. Later on, when collecting Lymnaea javanica Mouss. in the ponds of the Botanic Gardens, he secured the same species living in ponds in the open. From this place which is in open communication with the surrounding country by ditches and a stream it can easily spread into W. Java. It soon became evident that a new element of the Javanese fauna was lying before us. We have been trying to identify this new element and present the results in this periodical.