SCIENCE-GOSSIP. 



139 



measures— major diameter, 30 millimetres ; minor 

 diameter, 26 millimetres; altitude, 15 millimetres. 



Plectopylis villedaryi (figs. 60 a and b), from Lang- 

 son and Bac-ninh, Tonkin, was described and figured 

 by Mr. C. F. Ancey in " Le Naturaliste," 1888, 

 p. 71, f. 2. Mr. Pilsbry has illustrated the 

 armature in " Manual of Conchology," viii. (1893), 

 t. 43. f. 39. which I have been obliged to copy, 

 having only seen one unbroken specimen of this 

 species. The shell is solid, depressed, disk- 

 shaped, regularly ribbed with minute spiral 

 sculpture above, the ribs being particularly con- 

 spicuous in the wide funnel-shaped umbilicus. 

 There are six and a-half whorls, which increase 

 slowly and regularly, the last descending in front, 

 very convex and subangular around the umbilicus. 

 The aperture is very oblique, somewhat ear- 

 shaped, and the peristome is very much thickened 

 and reflexed, the margins being united by an 

 elevated tongue-shaped ridge on the parietal 



Fig. ea.— Plectopylis villedaryi. (a, original b, after Pilsbry.) 



callus. A stout curved plate is given off from this 

 ridge, rising obliquely (see fig. 60a). The parietal 

 armature is composed of a strong vertical plate 

 with two denticles anteriorly, one near the upper 

 and one near the lower extremity, the upper one 

 smaller, the lower one elongated (see fig. 606, 

 which gives the anterior view of both armatures). 

 The palatal armature consists of seven folds, the 

 first small and thin, near to and parallel with the 

 upper suture; the second, third, fourth and fifth 

 larger, oblique ; the sixth very minute and situated 

 to the rear of the others ; the seventh small, near 

 to and parallel with the lower suture (see fig. Gob). 

 The measurements given are : major diameter, 

 20 millimetres; minor diameter, 17 millimetres; 

 altitude, 9 millimetres. The shell in the British 

 Museum (shown in fig. 6oa) measures— major 

 diameter, 19 millimetres ; minor diameter, 16J 

 millimetres ; altitude, 8 millimetres. 



Plectopylis phlyaria (figs. 6ia-c), from Tonkin, was 

 described and figured, by Mr. Mabille, in " Bulletin 

 de la Societe Malacologique de France," iv. (1887), 

 p. 100, t. 2, ff. 1-3. Unfortunately the armature 

 does not appear to have been examined by Mr. 

 Mabille, for not only has he omitted to illustrate it, 

 but no mention is made of it in his diagnoses, and 

 to my great regret these important structures 



remain unknown to me. Not having been able 

 to obtain a specimen of this species I have been 

 under the necessity of copying Mr. Mabille's figures 

 and description. The shell is "openly umbilicated, 

 depressed discoid, thin, somewhat solid, scarcely 



Fig. di.— Plectopylis phlyaria. (After Mabille. 



shining, dull whitish under a deciduous, greyish, 

 hairy cuticle, arcuately striated, and seen under 

 a lens to be covered with imbricating lamellae. 

 Spire fiat, apex shining, smooth, corneous. Whorls 

 seven and a-half, narrow, convex, rather rapidly 

 and regularly increasing, separated by a deeply 

 impressed suture. The last whorl large, but little 

 wider than the preceding whorl if viewed from 

 above ; laterally compressed, obscurely angulated 

 at the periphery, deeply descending in front, 

 tortuous, a little convex beneath. Aperture half 

 round, toothed, the margins connected by a trans- 

 verse parietal lamina, behind which a dentiform 

 callus emerges ; peristome white, thick, reflexed. 

 Major diameter, 15 millimetres, minor diameter, 

 13 millimetres ; altitude, 5-5 millimetres." 

 (To be continued.) 



