1915.J G. K. GuDE: Mollusca, IV. 507 



ing, the upper horizontal and slightly arched, the outer straight 

 and obliquely descending, basal curved, columellar straight, 

 ascending. 



The parietal armature consists of a single, slightly oblique, 

 transverse plate, truncate below, where it is also slightly dilated 

 anteriorly, with a very slight anterior support at its upper extre- 

 mity, and posteriorly with two slight very low ridges, one each 

 near its two extremities, the upper obliquely descending and the 

 lower obliquely ascending towards the transverse plate. Below 

 the latter occurs a very short, slight, horizontal fold with a 

 second, still shorter fold posteriorly to it. The palatal armature 

 consists of six spiral folds ; the first short and slight, horizontal, 

 near the upper suture; the next four stouter and more elevated, 

 the second obliquely descending backwards, its posterior extre- 

 mity bifurcate; the third nearly horizontal, its anterior extremity 

 slightly bifurcate ; the fourth and fifth obliquely descending 

 backwards, their anterior extremity also slightly bifurcate ; the 

 sixth short, slight, horizontal, near the lower suture. 



Major diam. 7'25, minor 8"5 mm.; alt. 3*5 mm. 



Hab. — Yamne Valley, Abor Hills {Oakes). 



Type No. 3124 Bril. Mus. 



Its nearest relative is P. macromphaliis, but it differs from, 

 that species in having the palatal barriers in one series, instead of 

 two, and it therefore stands in the same relation to its all}^ as 

 does P. sowerhyi to P. plectostoma. It is also considerably larger. 

 The new species is named in commemoration of Dr. Gregorson, 

 Medical Officer, with Mr. Noel Williamson, who were both mur- 

 dered in 191 1 in the Abor country. 



Plectopylis (Endothyra) miriensis (G.-A. MS.), sp. n. 

 (PI. xH, figs. 3, za, 36, 3c, 3^). 



Shell sinistral, discoid, pale yellowish-corneous, widely um- 

 bilicated, the 3 nepionic whorls nearly smooth and shining, the 

 remainder covered with raised spiral lyrae, the interstices finely 

 and closely transversely striated. Whorls 6^, increasing slowly 

 and regularly, the last slightly dilated towards the mouth, not 

 constricted behind the peristome, slightly descending and shortly 

 deflexed in front, angulated above, slightly compressed below the 

 angulation, the underside convex. Spire almost plane, apex 

 projecting, suture channelled. Aperture oblique, rhomboid-auri- 

 culate; peristome white, thickened and reflexed, the margins 

 united by a thin callus on the parietal wall, without a ridge, but 

 with the edge crenulated, owing to the prominent spiral lyrae; 

 slightly notched at the lower junction with the peristome. 



The parietal armature consists of a short transverse plate, its 

 lower extremity a little obliquely deflexed towards the mouth, 

 provided anteriorly with a short, almost horizontal ridge below, 

 and an obliquely descending ridge above, a little stouter and 

 longer than the lower ; below the plate occurs a short thin bilobed 



