PLECTOTROPIS. 213 



Hctb. Burma: Ava (Oldham, Anderson); between Prome and 

 Tongoop, Arakan Hills (Blanford) ; Pegu (Stoliczka). India : 

 Assam (Stoliczka). 



When describing the species Benson referred to H. oculus as its 

 nearest ally. It is, however, much nearer to tapeina, from which 

 it may be distinguished by the wider and more open umbilicus, the 

 slightly blunter periphery, more depressed spire, and more closely 

 coiled whorls, for although considerably smaller in size it possesses 

 a whorl more. A third specimen on the same tablet in the 

 Benson collection, in fact, I refer to P. tapeina, var. alcowton- 

 yensis-, while measuring 16 mm. in diameter, it is only composed 

 of 5^ whorls, the last whorl is less deflected in front and a 

 little less angulated at the periphery, although the whorls are 

 more flattened. This variety appears to approximate still nearer 

 to P. oldhami, although usually more depressed in the spire, less 

 deflected in front, and possessing only five whorls. The latter, 

 however, is invariably more angulated around the umbilicus than 

 either P. tapeina or its variety akowtongensis. 



The shell recorded by Blanford * as H. oldhami from Siam is 

 quite distinct and belongs to Trachia, being nearer to nilagerica. 



186. Plectotropis nutans, Gude. 



Plectotropis nutans, Gude, Proc. Malac. Soc. London, xi, 1914, 

 p. 65, text-figure. 



Original description : " Shell depressed conoid, rather widely 

 and perspectively umbilicated, thin, light corneous under a pale 

 yellowish deciduous cuticle, finely and irregularly striated, 

 very minutely spirally striated above, the base covered with 

 much coarser, incised, slightly wavy spirals. Spire low, suture 

 linear, apex acute. Whorls 5)-5|, increasing slowly and regularly 

 at first, the last rather suddenly ; flattened above, the last convex 

 below, keeled at the periphery, the keel being rather pinched 

 above and below, angulated around the umbilicus, not dilated at 

 the mouth, very shortly and slightly descending in front. Aperture 

 oblique, subhastate, margins approaching, united by a very thin 

 callus on the parietal wall; peristome rather thin, scarcely thickened, 

 but distinctly expanded, slightly reflexed ; upper margin slightly 

 curved, forming an obtuse angle with the outer margin, which is 

 also slightly curved, the basal margin strongly curved, slightly 

 angulated at the junction with the columellar margin, which is 

 almost straight, ascending obliquely, triangularly dilated, but not 

 overhanging the umbilicus." (Gude.) 



Major diam. 16'5-17, minor 14-14'5 ; alt. 8 mm. 



Hob. India : Habiang, Garo Hills (Godwin-Austen) ; West 

 Khasia, Assam (Beddome). 



* Proc. Malac. Soc. London, v, 1903, p. 278. 



