LAND SNAILS FROM THAILAND — SOLEM 621 



T=atricallosus coloration 



Lc= simple, untwisted columella 



Pc=a twisted columella or columellar plait present. 



Thus the notation after a catalog number of "9 L, 3 S + Pc" indicates 

 that the set contained nine shells with leucoxanthus coloring and simple 

 columella and three shells with laidlawi coloration and a twisted 

 columella. Since most leucoxanthus, atricallosus, and laidlawi varia- 

 tions had simple columellas and most perakensis forms had twisted 

 columellas, it was thought necessary to list only the exceptions. 

 The following sets of Thailand A. atricallosus were examined: 



Peninsular Thailand. — Ban Huey Ta, west of Nakron Sritamarat: 

 USNM 405659 (juvenile) ; Chumporn, west side of the Gulf of Siam: USNM 

 420275 (juvenile); Sichon, southeast of Bandon: USNM 405903 (1 T) ; 

 USNM 405872 (4 T) ; Kao Luang, west of Nakron Sritamarat: USNM 

 419189 (2 T) ; Kao Chong, east of Trang: USNM 427306 (1 P) ; Kao Soi Dao, 

 west of Singora and southeast of Trang: USNM 427311 (4 P) ; Tha Lo, 

 southwest of Bandon: USNM 384157 and USNM 419151 (9 T, 4 T without 

 varices, 3 L, 1 S + Pc, 1 P+Lc). 



West Thailand. — Prachuab Kirikhan (=Koh Lak), west side Gulf of 

 Siam: USNM 427292 (5 T). 



Central Thailand.— Srakeo, near Krabin: USNM 419793 (1 P). 



Eastern Thailand.— Lem Sing, Chantabun: USNM 405864 (1 L, 1 

 L + Pc), USN^I 420286 (1 L) ; Kao Lem Sing, Sankambeng Range: USNM 

 384152 (3 L + Pc); Pak Chong (=Pak Jong): USNM 365463 (1 S). 



Southeast Thailand. — Nong Yang, east of Sriracha: USNM 384158 and 

 USNM 384158b (3 L, 7 L + Pc, 2 P, 2 S, 1 S + Pc) ; Nong Khor, near Sriracha: 

 USNM 363617 (juvenile), USNM 363616 and USNM 405861 (19 P, 2 P + Le, 

 13 L, 9 L + Pc, 1 T, 1 P + S), USNM 363619 (7 S, 2 S + Pc), USNM 367510 

 (6 L, 2 L + Pc, 1 P, 1 S) ; Hoi Yang, near Sriracha: USNM 420288 (3 P, 4 L), 

 USNM 4104S9 (2 L + Pc), USNM 420290 (1 S) ; Sriracha, Gulf of Siam: 

 USNM 405883 (worn), USNIM 427345 (1 L, 1 L + Pc, 1 S + Pc); Ban Sadet, 

 between Sriracha and Hupbon: USNM 363618 (1 L, 2 L + Pc); Chantabun 

 (=- Chantaburi) : USNM 427341 (1 P, 1 P + Lc) ; Kao Sabab, near Chantabun: 

 USNIM 427331 (worn, most Pc) ; USNM 529518 (1 L) ; Koh Kut, island in 

 Gulf of Siam: USNM 405835 (1 P + Lc) ; USNM 419788 (1 P) ; Kao Saming, 

 in coastal plain near Krat: USNM 419184 (juvenile); Krat ( = Trad), on 

 Krat River: USNM 405655 (3 L, 4 L + Pc, 3 S + Pc); Kao Bantad, east of 

 Krat near Cambodia: USNM 405858 (6 L + Pc, 1 P, 1 S, 1 S + Pc). 



The distribution of the color phases is obviously not uniform. 

 Thus, while two-thirds of the specimens from Peninsular Thailand 

 are of the atricallosus phase, only one of the 119 shells from Southeast 

 Thailand has the darkened parietal callus. Similarly, 21 of the 23 

 known laidlawi are from Southeast Thailand. The leucoxanthus and 

 perakensis color forms seem less restricted in area, and it is certain 

 that simple and twisted columellas occur in many localities. The 

 larger samples from Kao Bantad, Nong Khor, Nong Yang, Ki-at, and 

 Tha Lo contained a mixture of color forms and, while Southeastern 



