Plate 1 



Figures 1-10. — Amphidromus atricallosus (Gould): 1 (USNM 419189), typical form, from 

 Kao Luang, west of Nakron Sritamarat, Peninsular Thailand; 2 (CNHM 109473), variant 

 form with slight brownish suffusion, from Khao Luang, west of Prachuab Kirikhan, West 

 Thailand; 3 (USNM 363619), form laidlawi, new form, holotype, from Nong Khor, South- 

 east Thailand. Amphidromus areolatus (Pfeiffer): 4 (USNM 427307), color form 1, from 

 Kao Chong, Peninsular Thailand; 5 (USNM 361448), color form 2, from Tale Sap, Penin- 

 sular Thailand; 6 (USNM 363621), color form 4, from Krabin, Central Thailand; 7 (USNM 

 419193), color form 7, from Tha Lo, Peninsular Thailand. Amphidromus atricallosus 

 (Gould): 8 (USNM 405864), form leucoxanthus von Martens, from Lem Sing, Chantabun, 

 Eastern Thailand; 9 (USNM 420288), form perakensis Fulton, from Hoi Yang, near 

 Sriracha, Southeast Thailand. Amphidromus sinensis indistinctus Pilsbry: 10 (USNM 

 405863), from Ban Nam Kien, North Thailand. 



