624 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



the Anambas Islands. The USNM material was collected by W. L. 

 Abbott in 1899 and 1900. No soft parts are available. 



Amphidromus inversus annamiticus (Crosse and Fischer, 1863) 



Bulimus annamiticus Crosse and Fischer, 1863, Journ. de Conch., vol. 11, pp. 357- 



359 [Saigon]. 

 Amphidromus inversus annamiticus (Crosse and Fischer). — Laidlaw and Solem, 



1961, Fieldiana, Zool., vol. 41, no. 4, p. 561. 



Specimens of this subspecies were seen from Bandon, Peninsular 

 Thailand (USNM 361481), on trees in the town; Koh Sichang (USNM 

 405866), an island off Sriracha near the head of the Gulf of Siam, 

 Southeast Thailand; and Koh Samet (USNM 384154, USNM 384200, 

 USNM 419153, USNM 419804), an island in the Gulf of Siam, 

 Southeast Thailand. The shells from Bandon are much larger than 

 those from Koh Samet (see table 1), probably reflecting the well- 

 known small island dwarfing effect on land snails. Most specimens 

 have a white background color, but some have the reddish tint of 

 variety roseotincta von Moellendorft'. 



Amphidromus areolatus (Pfeiffer, 1861) 



Plate 1 (figs. 4-7) 



Bulimus areolatus Pfeiffer, 1861, Proc. Zool. Soc. London, 1861, p. 194 [Siam]. 

 Amphidromus areolatus (Pfeiffer). — Laidlaw and Solem, 1961, Fieldiana, Zool., 

 vol. 41, no. 4, p. 564. 



A number of diverse color forms are grouped with some hesitation. 

 Few specimens were available and only one of the color phases was 

 seen from several localities. Possibly some subspecific division may be 

 warranted when more material can be studied. The seven observed 

 color forms are: 



1. Three shells from Kao Chong (USNM 427307) in Peninsular 

 Thailand have two purplish red basal bands — the upper much narrower 

 than the lower — that are separated by an intense yellow band margined 

 by narrow white zones. There are slight traces of a reddish columellar 

 patch. The tip is purple and the spire white or pale yellow (pi. 1, 

 fig. 4). This pattern is the same as that of A. sinensis, which differs 

 in being a much larger, heavier and usually more globose shell. Both 

 measurable adults from Kao Chong are 24.7 mm. high with 6 whorls. 



2. Four shells from Tale Sap (USNM 361448), Peninsular Thai- 

 land, have the basal pattern of the above, with the addition of vague 

 streaks and spots on the upper portion of the spire. This is very close 

 to the pattern of A. sinensis var. gracilis Fulton, 1896 from Pegu, Bur- 

 ma, which may be a form of A. areolatus. The gracilis of Fulton is 

 stated to have four rows of spots on the upper spire, while the Tale Sap 

 shells have irregular blotches (pi. 1, fig. 5). The three measiu-able 



