316 PllOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



anterior valvse sinistrae elongatas, rugosus, dentes duo posteiiores 

 recti, gequales. Long. 131, alt. 50, diam. 24 mm. ' 



Mah. — Paliang River, Malay Peninsula. 



This species is remarkable for its elongate form. The colour of 

 the periostracum is dark olive-brown, with here and there a darker 

 concentric zone. There is also an indication of two or three obscure 

 rays on the posterior area between the rounded umbonal ridge and 

 the dorsal margin. The lines of growth are rather strong, and are 

 faintly sinuated at their anterior termination. 



The specimen described has been presented to the British Museum 

 (JS'atural History) by Mr. L. Lindsay, who possesses a second speci- 

 men. They were picked up on the banks of the Pahang about ten 

 years ago by a relative of Mr. Lindsay's. 



