A extremely rare land snail from Borneo - Vitrinula sp.
These photos show a rare species of land snails of the genus Vitrinula, probably Vitrinula muluensis (Stylommatophora - Ariophantidae), found on the climb up Gunung Api to the Pinnacles overlook, in Gunung Mulu National Park, Sarawak, Borneo.
The most interesting feature of these snails is that the animal has two mantle-lobes as metallic-colored tendrils covering part of front of shell, which continually lick the shell. Those tendrils are in fact a double penis which exceed the periphery of the shell and are a diagnostic feature of the genus.
Little is known about this rarely seen species, which is not surprising considering that they have a very restricted habitat in the karst area of Gunung Mulu, since as Clements et al. (2008) indicate, limestone karsts on tropical land masses are considered de facto habitat islands due to their isolation from one another by non-calcareous substrata; this spatial configuration limits gene flow and induces high levels of species endemism.
Photo credit: [Top: ©ccdoh1 | Locality: Gunung Api, Sarawak, Borneo, Malaysia (2009)] - [Bottom: ©Alan Cressler | Locality: Gunung Api, Gunung Mulu National Park, Sarawak, Borneo, Malaysia (2009)]
References:  - 
Snail with a giant forked penis that makes it look broken and glitched.