202 



DESCRIPTIONS OF NEW SPECIES OF MACROCHLAMYS AND 

 PSEULOBON FROM SIAM. 



By H. E. Preston, F.Z.S. 



Read \Wi November, 1908. 



Macrochlamys rex, n.sp. PI. YIII, Fig. 2. 



Shell narrowly perforate, somewliat tumid, semitran?parent, pale 

 yellowish horn colour, not polished above ; whorls 6i, sculptured 

 with fine transverse lines of growth ; suture impressed, margined 

 below ; base of shell polished, shining ; umbilicus narrow, deep ; 

 columella descending obliquely ; peristome simple ; aperture lunate. 

 Alt. 16, diam. maj. 30 ram. ; aperture, alt. 11, diam. 12 mm. 



Hab. — Nan-ko, Siam. 



Allied to M. pumicata, Morel., ^ but more tumid, and possesses a higher 

 spire than does that species ; the umbilicus is also slightly narrower, 

 the last whorl shows no sign of angulation at the periphery, the 

 columella descends more obliquely, the aperture is narrower, and 

 there is no indication of a violet coloration on the sutural margin. 



PSEUDODOK PONDEEOSA, U.Sp. PL VIII, Pig. 1. 



Shell solid, moderately convex, sub - trapezoidal, covered with a 

 coarse, black, scaly periostracum which becomes laminiferous towards 

 the posterior side ; anterior side bluntly rounded ; posterior side 

 rounded above, somewhat rostrate below ; dorsal margin slightly 

 arched ; ventral margin almost straight ; umbones large, prominent ; 

 interior of shell nacreous, iridescent, tinged with pinkish mauve, 

 deepening posteriorly. Long. 66, lat. 117 mm. 



Hah. — Nan-ko, Siam. 



^ Series Conch., xii, p. 248, pi. xii. 



