SCIENCE'GOSSIP. 



71 



received with P. magna, as above mentioned, I 

 propose to distinguish as Plectopylis lissochlamys. 

 Two specimens were sent to me by Miss Linter. 

 Dr. von Mollendorff, the German Consul in 

 Manila, Luzon, however, has obligingly sent me 

 for inspection several specimens of Plectopylis, 

 amongst which are two (labelled Plectopylis re/iiga) 

 which I refer to this new species. Plectopylis 

 lissochlamys differs from P. magna in being much 

 smaller and shining, as well as paler in colour ; the 

 shell in shape and texture resembling Plectopylis 

 piilvinaris, which, however, is a dextral shell (ante 

 vol. iii., page 180, fig. 25). It is more solid and 

 darker in colour than P. ponsonbyi and it is more 

 coarsely ribbed ; the two last whorls increase 

 more suddenly, and the last is not constricted 

 behind the peristome as is the case in P. ponsonbyi. 

 The two parietal plates (see fig. 53^) are much 

 thinner, and the anterior ridges of the anterior 

 plate much shorter and slighter than those of 

 P. ponsonbyi ; they are parallel instead of convergent 

 as in P. magna. A comparison of the figures will 

 indicate differences in the palatal armature. The 

 specimen figured is in my collection and measures 

 ig millimetres in diameter. Figs. 53^-^ are natural 

 size, while figs, ^^d-f are magnified. Fig. 53^ 

 shows the parietal and palatal armature from the 





Fig' 5l.—PlectopylU lissochlamys. 



posterior side ; fig. 53^ a part of the parietal wall 

 with its plates ; and fig. 53/ the inside of the outer 

 wall with its folds and denticles. 



Plectopylis quadrasi (figs. 54^-^) was described by 

 Dr. O. F. von Mollendorff, in the " Nachrichtsblatt 

 der Deutschen Malakozoologischen Gesellschaft,' 

 XXV., 1893, p. 172. It was collected near the 

 village of Siamsiam, in the Province of Caguayan, 

 Luzon, Philippine Islands. Only three species of 

 Plectopylis have hitherto been recorded from the 

 Philippine Islands, viz., the species now under con- 

 Palatal folds, 5 ; the three upper horizontal, thin, the first 

 and second with a denticle posteriorly ; the third deflected 

 posteriorly; the fourth vertical, the upper part deflexed 

 anteriorly, the lower part deflexed posteriorly, with two 

 denticles posteriorly, one about ihe middle and one near the 

 lower extremity ; the fifth short, horizontal, indented at the 

 middle, with a slight curved denticle posteriorly. — Major 

 diameier, ig-20 millimetres ; minor diameter, 16-17 milli- 

 metres ; axis, 5-7 millimelrc. — Habitat, Burma. — Type in 

 my collection. 



sideration, and P. trocJiospira and P. polyptychia, both 

 of which latter will be dealt with in a future paper. 

 As Plectopylis quadrasi has never been figured, I 



Fig. 54. — Plectopylis quadrasi. 



have much pleasure in now illustrating it. The 

 shell is dextral, openly umbilicated, depressed 

 conical, thin, dark horny brown, regularly ribbed 

 above and finely striated below. The suture is 

 impressed, and the spire a little elevated. It is 

 composed of six rounded whorls, which increase 

 very slowly and regularly, the last not descending 

 in front, keeled at the periphery, and obtusely 

 angled around the umbilicus, which is deep and 

 moderately wide. The aperture is diagonal, irregu- 

 larly heart-shaped, and the peristome is brown, 

 a little thickened and well reflexed, the margins 

 being a little convergent and united by a slightly 

 elevated, sinuous ridge. The parietal armature 

 consists of two parallel horizontal folds, which 

 extend over nearly half a whorl, the upper one 

 being the strongest and united to the ridge at the 

 aperture, while the lower one is thinner and dees 

 not reach quite so far ; at their posterior termina- 

 tions these two folds are united by a slight vertical 

 ridge, which projects a little beyond the upper 

 fold (see fig. ^^e, which shows the shell with the 

 outer wall removed as far as the peristome). The 

 palatal armature is composed of three short, 

 parallel horizontal folds at one-third of the cir- 

 cumference from the mouth (see fig. ^^c, which 

 shows the shell with part of the outer wall re- 

 moved, so as to expose the anterior view of the 

 palatal folds, and fig. 54^^, which shows the entire 

 shell with the palatal folds as they appear through 

 the shell-wall). The two specimens figured are 

 from Palanan, North Luzon, and are in my 

 collection ; they measure, major diameter, 3-5 milli- 

 metres ; minor diameter, 3 millimetres; axis, 175 

 millimetres. All the figures are enlarged. 



(To be continued.) 



