SCIENCE-GOSSIP. 



206 



are enlarged). Mr. Godwin-Austen (op. cit., p. 60S) 

 mentions six palatal folds, and his figure shows a 

 small one near the upper suture, of which, how- 

 ever, no trace is found in the specimen now 

 figured, which is from Sylhet, and is in Mr. 

 Ponsonby's collection; it measures n milli- 

 metres in diameter. I have already alluded to the 

 fact that Mr. Godwin-Austen found two vertical 

 parietal plates in one specimen (ante p. 204). 



Pkctopylis pinacis (figs. 32«-rf), from Sikkim, was 

 described by Mr. Benson in the " Annals and 



b c 



Fig. 32. — Pkctopylis pinacis. 



Magazine of Natural History" (3), iii, 1859, p. 268, 

 and (3), V, i860, p. 247. The shell was figured in 

 Hanley and Theobald's " Conchologia Indica," 

 t. 13, f. 5 (1870), and t. 84, ff. 1-4 (1872), while the 

 parietal armature was figured by Mr. Godwin- 

 Austen in the " Proceedings of the Zoological 

 Society," 1874, t. 74, f. i. Professor von Martens 

 described what he thought was a new form, 

 under the name of Helix {Gorilla) pettos, in 

 the " Malakozoologische Blatter," xv, (1868), 

 p. 158, and this was figured by Dr. Pfeiffer in 

 " Novitates Conchologicae," iii, (1869), t. loi, 

 ff. 7-9 ; the type specimen, which is in the 

 " Konigliche Museum fiir Naturkunde," Berlin, 

 was obligingly sent to me for inspection by 

 Professor von Martens, with permission to open it ; 

 he suspected that it might probably be the same as 

 Pkctopylis pinacis, and upon opening the shell this 

 proved to be the case, the armature being identical, 

 while no differences could be detected in the shells 

 themselves. Under these circumstances Professor 

 von Martens' name becomes a synonym of the 

 species now under consideration. The shell is 

 sinistral, disk-shaped, pale corneous, widely 

 umbilicated, finely regularly ribbed and decussated 

 by spiral lines, composed of seven slowly increasing 

 whorls, the last comparatively wide and a little 

 deflexed anteriorly, and angulated at the periphery ; 

 the peristome is thickened and reflexed, its margins 

 united by the slightly raised, very flexuous, ridge 

 of the parietal callus, which- has a slight notch at 

 the junctions above and below. The parietal 



armature (fig. 321;), consists of a single strong 

 vertical plate, which is strongly abruptly deflected 

 anteriorly at the lower extremity, and gives off 

 posteriorly a club-shaped support ; the upper 

 extremity gives off two slight supports, one on 

 either side, the posterior one horizontal, and the 

 anterior one a little lower, oblique, and very 

 short ; a little below the posterior support occurs a 

 small denticle ; a free, thin horizontal fold is found 

 below the vertical plate ; see also fig. 32a, which shows 

 the shell with a portion of the outer wall removed, 

 exposing the parietal and palatal armatures from 

 the anterior side, and fig. 326, which shows the 

 folds from the posterior side. The palatal arma- 

 ture consists of : first, a thin horizontal fold near 

 the suture ; secondly, a stronger horizontal fold, 

 deflexed in the middle ; thirdly and fourthly, two 

 shorter, but stronger, equal and parallel folds 

 descending obliquely ; fifthly a crescent-shaped 

 fold placed obliquely with the concave side facing 

 the aperture (the lower surfaces of these folds are 

 seen in fig. 32a, their upper surfaces in fig. 32?)) ; 

 sixthly, a smaller horizontal fold, which becomes 

 attenuated posteriorly (see fig. 32^) ; two minute, 

 elongated denticles, one below the other, and 

 placed at right angles to each other, occur 

 between the first and second folds, near their 

 posterior terminations. The specimen figured is 

 from Darjeeling, and is in Mr. Ponsonby's collec- 

 tion ; it measures 15 millimetres in diameter. 

 A specimen in my collection, also from Dar- 

 jeeling, measures 14 millimetres. Mr. Godwin- 

 Austen's figure, quoted supra, shows a short free 

 horizontal fold above the vertical parietal plate ; 

 no trace of this fold can be seen in either of the 

 two specimens examined, neither does it occur in 

 the specimen in the Berlin Museum. 



Plectopylis nagacnsis (figs, 33^-^), was described 

 and figured in the " Proceedings of the Zoological 



Fig- 33- — Plectopylis nagnensts. 



Society," 1874, p. 609., t. 73, f. 4, by Mr. Godwin- 

 Austen, who found the species at Prowi, at the 

 head of the Lauier River, Naga Hills, Assam. 

 The shell is sinistral, widely umbilicated, disk- 

 shaped, with a conical, raised spire, of a dark 



