88 



HBLICIDiE. 



fine close flaxy epidermal striation, with four lines of long hairs 

 arranged upon the periphery of the body-whorl — two closely 

 adjacent and running with the keel above, one around the 

 umbilical depression, and one intermediate. Spire depressedly 

 convex, suture well marked, apex rounded. Whorls seven, closely 

 wound, side of the last very oblique belo^^' and flattened, becoming 

 rounder near the aperture, where it descends very slightly. 

 Aperture wide, semi-ovate, very oblique, and slightly reflected 

 on the margin. Peristome not thickened, continuous over the 

 parietal side. The internal barriers are not visible on looking 

 into the aperture. The parietal vertical lamina is simple, with 

 only a slight horizontal support above on the posterior side ■^ a 

 very short double-knobbed horizontal parietal lamella is situated 

 imn)ediately below it. Palatal plicae double, in two rows, the two 

 apical or highest in position being united together by a low ridge ; 

 the posterior row are somewhat obliquely arranged." (Gochvin- 

 Ansten.) 



Major diam. 20, min. 17*3 millim. ; alt. axis 8-5 millim. 



Ilab. Assam : Khasi Hills. 



Plectopylis f\dtoni is allied on the one hand to P. andersoni, the 

 parietal armature being almost identical, while the arrangement 

 and structure of the palatal folds connect it on the other hand 

 \\ith P. plectostoma. The parietal armature consists of a single 

 strong vertical plate (see flg. 36 a). Lt.-Col. Godwin-Austen, 

 in describing the armature, states that the parietal plate ha» only 

 a shght horizontal support above on the posterior side ; in speci- 

 mens in my possession, however, this plate has a similar support 

 below ; these supports consist of a tooth united to the vertical 



a 



b 



Fig. 36. — Plectopi/lis f niton i. 



plate by a slight callosity. Below this is a short thin horizontal 

 plate, a little indented in the middle. Tlie palatal armature (see 

 tig. 36 b) consists of : first, a short horizontal fold, close to and 

 parallel with the suture ; secondly, a longer and stouter horizontal 

 flexuous fold ; thirdly, another horizontal fold, slightly indented 

 in the middle and deflected posteriorly at an obtuse angle : fourthly 

 and fifthly, two series each of two short horizontal folds, the 

 anterior ones slightly oblique, with their lower ends towards the 

 ajierture, and the posterior ones deflected at an obtuse angle 

 posteriorly ; and sixthly, near the base, a short slightly bent fold, 

 with the convex side turned towards the lower suture. The 

 specimen figured, which is not quite mature, bears a second 



