16 PROCEEDINGS OF THE MALACOLOGICAL SOCIETT. 



interclum cum ilente parvo auxiliari parallelo juxta mari-inera ex- 

 ternam sito ; dens posterior elongatus, duobus paribus denies duo 

 posteriores valvae sinistrse seqxie elongati ; dens anticus interiore psene 

 obsoletus ; cicatrix antica alta, postica minime profunda ; ligamentum 

 prominens. Long. 77, alt. 51'5, diam. 37 mm. 

 Hab. — Kiver at Pajakombo. 



CoRBicuLA MoussoNi, Desh. 

 Hab. — lliver Kwantan, affluent of the Indragiri, and the Souliki Range. 



One Corbicula from the River Kwantan is not included in this 

 paper, as its affinities are not at present quite clear. 



My best thanks are due to Mr. E. A. Smith for access to the speci- 

 mens and literature in the British Museum, and to Mr. E. R. Sykes 

 for the loan of a specimen of Cyclophorus pliciferm and for useful 

 information. 



EXPLANATION OF PLATE II. 



Figs. 1, 2. Cyclophorus {Atnplus) eximins, var. Roiiyeri, n.var. 



,, 3, 4. Xesta eornicen, n.sp. 



., 5, 6. Limncea Bongsonensis, n.sp. 



Fig. 7. Melania Syhesi, n.sp. 



,, 8. Meiania curvicosta, yar. Prestoil/itin, Q.\m-. 



,, 9. Unio Pajakomboensis, n.sp. 



,, 10. Hinge of right valve. 



,, 11. Hinge of left valve. 



