216 PEOCEEDINGS OP THE MALACOLOGICAL SOCIETY. 



has a short ridge on both sides ; below it occurs a moderately long, free, 

 obliquely descending fold ; the posterior plate is curved and descends 

 backwards, with a short support posteriorly at the upper extremity. 



Palatal armature consisting of six folds, the first low, thin, straight, 

 horizontal, the other fi.ve more raised; the second very long, the anterior 

 portion horizontal, the posterior portion vertically descending, with 

 a slight denticle behind and a diffuse callus below its extremity, the 

 next three curved, oblique, bifurcated posteriorly ; sixth oblique, 

 straight, short. Diam. maj. 12, min. 10*5 mm. ; alt. 5 mm. 



Hah. — Nat-Son. Type in my collection. 



This new species is named in honour of Mr. Eichard W. Goulding, 

 the Librarian at Welbeck Abbey, who has frequently favoured me 

 with advice and assistance. The shell is allied to P. anterides, but the 

 anterior parietal plate is not provided with the buttresses so conspicuous 

 a feature in that species, and the plate is united to the upper horizontal 

 fold, which is much longer than in P. anterides, as is the lower free 

 horizontal fold ; while the palatal folds are not united by a vertical 

 callus and they overlap when viewed from the front, whereas in 

 -P. anterides they have much more space between. 



A larger form from Pac-Kha, measuring 14 mm. in diameter, shows 

 traces of hybrid origin, having the overlapping palatal folds of 

 P. Gouldingi with the free upper horizontal parietal fold and the 

 buttresses of P. anterides. A still larger form from the same place 

 (16 mm.), while otherwise agreeing in both sets of armature, is pro- 

 vided with buttresses. The species is also allied to P. tenuis, but the 

 anterior vertical parietal plate in that species has no support anteriorly 

 at its lower extremity, and has a free fold above it, while its palatal 

 folds aj'e not bifurcate. 



Plectopylis anterides, n.sp. PL IX, Fig. 2. 



Shell dextral, widely umbilicated, discoid, from pale to ruddy 

 corneous, the nepionic whorl shining, the later ones dull, covered 

 with a deciduous cuticle. Spire flat, apex low, suture a little 

 impressed. Whorls 6, slightly convex above, rounded at the side and 

 below, obtusely angulated round the wide, rather shallow umbilicus, 

 increasing slowly and regularly, last scarcely dilated towards the 

 mouth, shortly and abruptly deflexed in front. Aperture subcircular, 

 oblique, margins distant ; peristome white, thickened, and reflexed, 

 the margins united by a strongly raised flexuous ridge ; upper margin 

 at first slightly ascending, arcuate, outer and basal regularly curved, 

 columellar straight. 



Parietal armature composed of two vertical plates, the anterior 

 giving off at its lower extremity a short ridge on each side, with 

 one or two buttresses anteriorly, and having a free, horizontal, 

 thin, longish fold above and below ; the posterior curved, descending 

 backwards, with a short ridge posteriorly above. 



Palatal armature composed of six folds, the first short, thin, low, 

 horizontal, with a short descending ridge at its posterior extremity, 

 the others raised ; the second long, its anterior portion horizontal, its 

 posterior extremity descending and bifurcate ; the third has the 



