264 



SCIENCE-GOSSIP. 



The shell is dextral, disk-shaped, deeply and rather 

 widely unbilicated, pale ochreous brown, irregularly 

 marked with a darker shade, regularly and finely 

 striated, with many raised spiral ridges. The 

 spire is depressed-conical, the apex prominent, and 

 the suture slightly impressed. There are seven 

 whorls, flattened above and tumid below, the last 

 scarcely descending in front. The aperture is 

 oblique, a little depressed above, somewhat ear- 

 shaped ; the peristome is white, a little thickened 

 and reflexed, its margins being united by a strong, 

 raised, curved ridge on the parietal callus, and 

 notched above and below at the junctions. The 

 parietal armature consists of a single, strong, 

 vertical plate, which is obliquely deflected towards 

 the aperture ; it has two slight supports posteriorly 

 — the lower a little deflected, the upper obliquely 

 raised — and gives off anteriorly, at the upper 

 extremity, a long, slightly raised ridge ; a minute 

 denticle occurs just below the vertical plate (see 

 fig. 6gd, which gives an enlarged view of the shell 

 with a portion of the outer wall removed). The 

 palatal armature consists of six more or less 

 horizontal folds : the first very minute near the 

 suture ; the second long and descending a little 

 obliquely towards the middle, with the posterior 

 end suddenly raised ; the third and fourth also 

 descending a little obliquely, their posterior ex- 

 tremities dilated, almost bifurcated ; the fifth 

 also descending a little, its posterior termination 

 suddenly deflected ; the sixth, horizontal, with a 

 minute denticle above, and an elongated one a 

 little further back, below the posterior termination 

 of the fold (see fig. 69^, which shows the inside of 

 the outer wall of the shell). The figures are taken 

 from the type specimens in the collection of Lieut. - 

 Colonel Godwin-Austen, who has obligingly lent 

 them to me for this purpose. The shell measures: 

 major diameter, 10-5-11 millimetres ; minor 

 diameter, 9-95 millimetres ; altitude, 5 millimetres. 

 Figs. 6ga-c are of natural size, while figs. 6gd-g 

 are enlarged ; e shows the armatures from the 

 anterior and/ from the posterior side. 



Plectopylis blanda (i) (figs, joa-f). A single speci- 



men received by the writer under the name of 

 Plectopylis minor, from the Naga Hills, was sent 

 to Lieut. -Colonel Godwin-Austen for examination, 

 and was found by him to be a new species. It 

 differs from Plectopylis minor in being larger and 

 more elevated, and having a wider and deeper 

 umbilicus. The parietal armature differs in 

 having an additional fold above the vertical plate, 

 and the anterior denticles are almost united to this 

 fold. The palatal armature differs in the posterior 

 folds being very short and almost reduced to 

 denticles. Figs, yoa-c show the shell in three 



^ J 



Fig. yo.— Plectopylis blanda. 



different aspects. Fig. jod gives the posterior 

 view of the two armatures ; e, the inside of the 

 outer wall ; and /, a portion of the parietal wall, 

 with its plate and folds. All the figures are 

 enlarged. 



Erratum. — A typographical error occurs ante 

 p. 231— the name Plectopylis leucochilus should read 

 Plectopylis leucochila. 



(To be continued.) 



{}) Plectopylis blanda, n. sp. (figs, yoa-f). — Shell sinistral, 

 depressed conical, widely and deeply umbilicated, whitish- 

 corneous, finely and regularly ribbed. Spire conical, apex 

 prominent, suture distinctly impressed. Whorls six, tumid 

 above, rounded below, increasing very slowly and regularly, 

 the last not descending in front, angulated above the peri- 

 phery and round the wide perspective umbilicus. The 

 cuticle is produced into deciduous hairs on the ribs, forming 

 spiral rows. Aperture oblique, lunate, a little flattened on 

 the upper, outer margin. Peristome white, a little thickened 

 and reflexed, the margins united by a slight, flexuous ridge on 

 the parietal callus. Parietal wall with a strong, vertical 

 plate, slightly deflected anteriorly and having two minute 

 denticles posteriorly, the upper vertically the lower hori- 

 zontally elongated. A very thin horizontal fold occurs below 

 the vertical plate and a very short fold above it. Palatal 

 folds in two series ; the anterior consisting of six thin hori- 

 zontal folds, the first and sixth a little shorter and placed a 

 little further back than the other four; the posterior series 

 consists of four very short folds or denticles. — Major 

 diameter, 6 millimetres ; minor diameter, 5 millimetres ; 

 altitude, 3 millimetres. Habitat— Naga Hills, Assam.— Type 

 in my collectic.%. 



