Oi} a neio Specks o/Plectopylis/rowi Tonkin. 313 



XLII. — Description of a new Species 0/ Plectopylis from 

 Tonkin. By G. K. Gude, F.Z.S. 



Plectopylis lepida, sp. n. 



Shell dextral, deeply and widely umbilicated, pale corneous, 

 striated and decussated with microscopic spiral lines above 

 the periphery, smoother below. Spire depressed, apex raised, 

 suture shallow. Whorls 8, slightly convex, increasing 

 slowly and regularly ; the last widening rather suddenly, 

 twice as wide as the penultimate, descending shortly in front. 

 Aperture oblique, lunate. Peristome a little thickened and 

 reflexed; the margins united by a very slight ridge on the 

 paiietal callus. Parietal wall with a slight denticle near the 

 ridge. Parietal armature consists of a strong curved plate, 

 obliquely descending towards the aperture, and giving off" 

 anteriorly two long ridges, the upper low and rather thin, the 

 lower stronger ; on the posterior side the plate gives off at 

 its upper extremity a very short support. Palatal armature 

 composed of six folds : the first (upper) thin, horizontal, 

 parallel with the suture; the second also horizontal, longer 

 than the first, descending slightly posteriorly, where it is a 

 little bifurcated ; the third, fourth, and fifth vertical, semi- 

 circular, curved (the convex side towards the aperture), and 

 united by a low ridge ; the sixth horizontal, rather long and 

 thin, parallel with the lower suture. 



Major diam. 13, minor 11"5, alt. Cy6 mm. 



Jdah. Tonkin, Tinh-Tuc. Type in my collection. 



This new species is the smallest of the Tonkinese forms, 

 and differs considerably in the armature from its allies. Tiie 

 vertical palatal folds overlap the parietal plate, leaving 

 scarcely any room for the animal to emerge. The species is 

 unique among its allies in having two horizontal palatal folds 

 above the three vertical folds. In this respect, liowever, it 

 shows a certain affinity with P. achatina and its allies ; and 

 this affinity is further evidenced by the fact that the three 

 vertical folds are united by a low ridge ; the sinuses between 

 these folds would only have to be filled in to constitute the 

 single vertical plate characteristic of the group of P. achatina. 

 P. lepida should be placed next to P. Villedaryi. 



The single specimen was received from a French dealer. 



