Microparmarion malayanus (Collinge, 1903)
Collinge (1903) original descriptions on Parmarion malayana – “Animal fawn coloured, with faint dirty blue streak at each side of the dorsum posterior-laterally. Mantle fawn coloured with irregular deep brown markings; keeled on the left side. Head marked by two prominent dark blue bands, which extend on to the bases of the upper tentacles. Rugae faint, small, and oval shaped. Peripodial groove distinct. Foot-fringe same colour as the body, with faint lineoles. Foot-sole dirty yellow, with median and lateral planes. Shell oval in form, amber coloured, semi-transparent and membraneous; whorls two-and-a-half; the first, which is very small, being calcareous.”
“The generative organs in general form agree with those of other Malayan species, there is one notable difference, however, viz., the penis does not exhibit the beak-like distal end, common to so many species. The form of the species reminds one of this same organ in some species of Girasia, Gray. The vestibule is wide, and leading into it in the middle portion is the vagina, a long, wide, spacious tube, which distally receives the short duct of the receptaculum seminis. The free oviduct is very short and scarcely differentiated from the common duct, which is thrown into a single fold and richly convoluted. The penis commences as a wide muscular tube, an at the point where the retractor muscle is inserted becomes bulbous, and make a sharp turn upon itself, the gradually tapering passes into the vas deferens which joins the common duct on the opposite side to and just above the opening of the receptacular duct. Internally the lumen of the penis does not agree with the external form, agreeing in this character with the genus Microparmarion, Simr. At the proximal end the penis is a fine canal which makes a bend to the right side and then to the left side, it is then continued as a fine tube to the region where the penis is folded upon itself; here it expands into a sac-like chamber which is connected by a tube-like portion with a further dilation, which latter gradually lessens in size, continuing on the ventral side of the organs, and ultimately passes into the vas deferens.” (Collinge, 1903)
Parmarion malayana – “Length (in alcohol), 30 mm. Shell dimensions; Maj. Diam. 6.5; min. diam. 4 mm.” (Collinge, 1903)
Predators of Microparmarion malayanus – “Malaysian wood rat, Rattus tiomanicus (Miller); Pacific rat, Rattus exulans (Peale); Rice field rat, Rattus argentiventer (Robinson & Kloss).” (Limm, 1966)
Type locality – “Bukit Besar, Nawngchik, 2500 feet” (Collinge, 1903)