GUDE : ON SOME KNOWN SPECIES OF PLECTOPYLIS. 



49 



^ 



d. e. f. 



Fig. 4. — riedopylis Icpida. 



a. b. c. Shell, natural size. 



d. Parietal armature. e. Palatal armature. 



f. Posterior view of parietal and palatal armature. 



the animal to emerge. The species is unique among its alh'es in 

 having two horizontal palatal folds above the three vertical folds. 

 In this respect it shows a certain affinity with the Burmese 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. acliatina. 



P 



a. b. c. d. 



Fig. ^.— Pledopylis plcdostomaw. exscrta. 



a. b. c. Shell, natural size, 

 d. Outline of the spire, enlarged. 



Plectopylis plectostoma var. exserta, n.v. Figs. 5a— d. 



Differs from the type in the peripheral keel being exserted. The 

 shell is also larger and more solid. More than thirty specimens were 

 received from a native collector. Figure 5d shows the outline of the 

 spire enlarged. 



Major diam. io"5, minor 975 ; alt. 7 mm. 



Hah. — Khasi Hills, Assam. 7't/pe in my collection. 



