30 PROCEEDTNfiS OF TUE MALACOLOGICAL SOCTKTY. 



of C. Sumatrana, and therefore I do not describe it as distinct. The 

 dimensions of the specimen figured (which is in my collection) are as 

 follows: — alt. 17}, diam. 4 mm.; alt. apcrt. 4f, lat. apert. 3 mm. 



There are four boxes of shells in the liritish Museum of this variety ; 

 one from Paio, one from Kepahiang, and the others labelled only 

 " Sumatra " ; one set come from C. Bock and are part of the collection 

 described by him.^ They vary in colour, from very dusky, through an 

 intermediate light brown, up to an albino specimen, collected by 

 Bock. They also vary considerably in the colour of the inside of the 

 mouth and in the relative proportions of length and breadth of shell. 



The Sumatran species fall into two groups : — («) lamella sub- 

 columellaris emersa ; C. obesa, (enigmatica, Melvilli. {h) lamella sub- 

 columellaris immersa ; C. Sumatrana, exciirrens, alticola. 



Divided by the plica? palatalos they are : — having 5-6 plicae, 

 C. Sumatrana (occasionally in the var. vicaria only 4) ; having 4 plicss, 

 C. obesa, alticola, (enigmatlca ; having 3 plicae, C. Melvilli ; having a 

 lunella, C. excurrens ; of those having 4 plicas the plica principalis is 

 large in all. 



In C. obesa they diminish as you descend but never become very 

 small ; in C. alticola they diminisli in the same way and the lowest 

 become punctiform ; while in C. (cnigmatica the second and fovu'th are 

 of equal size and larger than the third. 



The chief references are : — 



Von Martens. Monatsberichte K. Preuss. Akad. 1864, pp. 270 and 527. 

 „ Preuss. Exped. N.O. Asien, Zool. Thl. Bd. ii. 1867. 



,, in M. Weber: Zool. Ergcbn. Reise Mederland. Ind. ii, 1891, 



pp. 209-63. 



I have to return many thanks to Dr. Boettger for kind suggestions 

 and help. 



1 Proc. Zool. Soc. ISSl, pp. 628-35. 



