46 RECENTLY DESCRIBED SPECIES OF PLECTOPYLIS. 



which are distinct from the type and appear to be worthy of a 

 varietal name, Besides being larger and more conical than the 

 type, they are also distinctly keeled at the periphery and have 

 three distinct raised ridges on the upper side, revolving as far as 

 the fourth whorl. I name this form Plcctopylis plcctostoma var. 

 tricarinata. The entire shell is shown, enlarged, in fig. 2 a, while 

 a portion of the last whorl, more enlarged, is shown in fig. 2b. 

 The armature is identical with that of the type. {Ibid, p. 275). 



Figure 2.— Plcctopylis pledostoma var. tricaiinaia, Glide. 



Plectopylis affinis, Gude. 



Shell sinistral, somewhat ividely umbilicated, disc-shaped, 

 pale yellowish, corneous, translucent, radiately plicate, decussated by 

 spiral lines above, smoother and shining below. Whorls 7, narrow, 

 increasing slowl}-, the last widening towards the aperture, and 

 descending a little in front, rounded dihowQ, flattened below ; four 

 lines of soft pilose hairs pass round the whole length of the body 

 whorl, the first on the angulated periphery, the second a little 

 below it, the third midway between the second and fourth, 

 which is near the umbilicus. Aperture ear-shaped, elongated 

 vertically ; peristome white, thickened and reflexed, upper margin 

 a little depressed ; the raised flexuous ridge on the parietal callus is 

 separated from the margins by a slight notch. Umbilicus deep 

 and moderately 7<'ide. The parietal armature consists of a 

 vertical plate with two short supports anteriorl\', one above and 

 one below, and two elongated denticles posteriorly, one above 

 and one below ; tziJO free, short, horizontal folds in a line occur 

 belov/ the vertical plate. The palatal armature is composed of 

 six folds, the first and sixth short, thin and horizontal, the others 

 longer and broader ; the second a little indented in the middle, 

 with the posterior termination raised obliquely ; the third is 

 notched in the middle, and deflects obliquely posteriorly ; the 

 fourth and fifth are in two series separated by a short space, the 

 anterior portion straight and horizontal, the posterior portion 

 crescent-shaped and obliquely descending. — Major diameter, 10 

 millimetres ; minor diameter, 9 millimetres ; axis, ^.5 milli- 

 metres. — Habitat, Khasia Hills, Assam. — Type in my collection. 



