— 352 — 



Peristome a little thickened and reflexed, upper raargiii 

 arcuate, outerand basai curved, columellar nearly straight, 

 ascending obliquely and slightly impinging upon tlie um- 

 bilicus. 



Pariétal armature (fig. 3"^), coraposed of two vertical 

 divergent plates, the anterior one shortest, with a low 

 parallel ridge posteriorly, the upper extremity truncate, 

 the lower dilated, with a short support on each side; 

 above it occurs a short free horizontal fold, level with the 

 upper extremity of the posterior plate which bears a 

 short support posteriorly above and is obliquely reflexed 

 posteriorly and attenuated below. 



Palatal armature (fig. 3©), composed of six folds, the 



Fig. 3a 



Fig. 3d 



^ 



Fig. 3e 



first low, nearly parallel with and close to the upper su- 

 ture, the others semicircular ; the second nearly horizontal 

 with a slight elougated denticle posteriorly ; the third, 

 fourth, and fifth obliquely ascending forwards each giving 

 ofï from the posterior extremity above an obliquely ascen- 

 ding short low fold ; the sixth nearly horizontal, slightly 

 notched near its posterior extremity. 



Diam maj. : 13 mm, ; min. 11 mm. ; ait. 7 mm. 



Hab. : Quang Huyen, Tonkin. 



Type in the collection of the School of Mines, Paris. 



This new species is related to P. tenuis which il resem- 

 bles in the pariétal armature, but the anterior horizontal 

 plate, which in P. tenuis obliquely descends backwards is 

 hère directed towards the aperture, and the lower hori- 



