Plectostoma austeni (E. A. Smith, 1894) Figures 12A, 48C

Opisthostoma austeni E. A. Smith, 1894a: 272-273.

Type locality.

"Rumbang, Sarawak".

Material examined.

Gunung Doya: ME 0248, ME 9013, ME 9244. Gunung Kapor: ME 0255. Lobang Angin: ME 0250, ME 8734, ME 8744, ME 9180. Gunung Batu: ME 0249, ME 0253, ME 0259, ME 8794.

Distribution in Borneo.

Sarawak: Kuching and Serian divisions. Endemic to Borneo.

Remarks.

Living snails were observed foraging inside the rock crevices and cave walls, away from direct exposure to light. A single sinistral shell was found within the normal dextral populations.