PLECTOPYLIS. 97 



situated immediately under it. Palatal plicae 0, horizontal, the 

 first and upper small, the remainder about equal in size. 



"Major diam. 12, minor 11 mm.; alt. 6 mm." (Godivin- Austen.) 



Bab. India : Prowi, head of the Lauier .River, Naga Hills, 

 Assam. 



A dwarfed variety is mentioned by Lt.-Col. G-od win-Austen, 

 1. c. p. 610, from Sikhami, on the lowest part of the main water- 

 shed of the Burrail, measuring only : major diam. 8, minor 

 6-75 mm. ; alt. 3 mm. 



The parietal armature consists of a strong vertical plate, a 

 little deflected posteriorly at the lower extremity, where it 

 terminates in a short strong ridge ; it also has a short support 

 a little higher up on the anterior side, and another short ridge 

 on the posterior side at the upper extremity. Below this plate 

 is a free thin horizontal fold, and a little above the middle of the 

 plate, a short distance from it, rises a strong horizontal plate, 

 which runs parallel with the whorl, and descends a little at the 

 aperture, where it is united with the raised ridge of the parietal 

 callus (see fig. 42 a and 6, which show the shell with part of the 

 outer wall removed). 



The palatal armature consists of : first, a thin bilobed horizontal 

 fold near the upper suture ; secondly, a stronger horizontal fold, 

 with a small denticle at its posterior termination (between these 

 two folds, in a line with their posterior terminations, occurs a 

 minute denticle) ; thirdly, a horizontal fold, descending a little 

 posteriorly, where it is slightly notched ; fourthly, a similar 

 horizontal fold deflected posteriorly at first, then slightly 

 raised and notched ; fifthly, a shorter but stronger horizontal 

 fold with the posterior end more strongly deflected, and also 

 slightly notched ; sixthly, a thinner but longer horizontal fold 

 near the lower suture, attenuated anteriorly (see fig. 42 d, which 

 shows the inner side of the outer shell-wall with its palatal folds). 



Between the posterior terminations of the fifth and sixth folds 

 occurs a very slight thin fold extending much further posteriorly 

 than the main folds ; this may prove not to be constant ; it is 

 not mentioned by Lt.-Col. Godwin-Austen in his description. 

 The specimen figured is in Mr. Ponsonby's collection, and, 

 measures : major diam. 11*5, minor, 10 mm. ; alt. 5'5 mm. 



92. Plectopylis kengtungensis, Gude. 



Plectopylis (Cherstecia) kengtungensis, Gude, Proc. Malac. Soc. 

 London, xi, 1914, p. 54, with text-figure. 



Original description : " Shell sinistral, widely umbilicated, 

 discoid, corneous. Whorls 6|, narrow, increasing slowly and 

 regularly, somewhat flattened above, rounded below, the last 

 abruptly and shortly descending in front and slightly dilated at 

 the mouth. Spire a little raised, suture impressed. Aperture 

 obovate, peristome slightly thickened and reflected ; upper margin 

 nearly straight, outer rounded, columellar ascending ; parietal 



n 



