PLEOTOTROPIB. 215 



Hah. India : Silhet (Benson) ; Khasi Hills, Assam {Godwin- 

 Austen, StoliczJca) , Cherrapoonjee, Assam (Andei-son) ; Harmutti, 

 Dafla Hills {Godiuin- Austen, Stoliczica). Burma: Prome {Fea). 



The species varies considerably in size, specimens from Cherra- 

 poonjee, in the writer's possession, sent by a native collector, 

 ranging from ll"5-105-6 to 16-o-14"75-9"5 mm. A specimen in 

 the Benson collection is abnormally high in the spire, measuring : 

 diam. ll'o, alt. 8*75 mm. 



P. topeina has been confused with P. rotatoria, v. d. Busch, a 

 Java species, and P. trichotropis, Pfr., a Chinese form. Nevill, in 

 fact, records a variety rotatoria, Buchanan (apparently a misprint 

 for V. d. Busch), from Bhamo, Manwyne, and Shan Hills near 

 Ava, and Assam. P. rotatoria, however, is quite distinct, having 

 more flattened whorls, a sharp keel at the periphery, and a deeper 

 and wider umbilicus. Tapparoue Canefri recognised that the 

 form recorded as var. rotatoria was distinct from that species, and 

 he separated the Burmese form, thus named, as P. theobaJdiana. 



Nevill regarded akoivtongensis and rotatoria as doubtfully sepa- 

 rable *, thinking the differences might " be merely perhaps 

 incidental to individuals, and not even to local races." 



In the same paper (p. 19) he refers some specimens taken by 

 Godwin-Austen in the Khasi Hills to P. trichotropis, Pfr., stating 

 his belief that one of them is represented by pi. 15, fig. 4, of 

 Conch. Ind. 



I do not think this Chinese species occurs in the Indian region, 

 and am firmly convinced that Nevill wrongly identified his speci- 

 mens. P. tricliotropis, A\hich bears no resemblance to the figure 

 quoted, has a more trochoid spire, the whorls are more flattened 

 above and the suture is consequently much shallower, while the 

 whorls below are much more inflated ; the keel is more pronounced 

 and situate higher up, and is, moreover, ornamented with a fringe, 

 a feature I have never observed in any of the Assam or Burma 

 shells, in however fresh condition. The aperture further diff'ers 

 in being less dilated transversely, being in fact almost auriculate, 

 and the columellar margin is more oblique and, being straight, it 

 forms an obtuse angle with the basal margin. The umbilicus, too, 

 although not wider is more open and distinctly angulated. The 

 sculpture, finally, is also quite diff"erent in tricliotropis, consisting 

 of elongated squamte, both above and below. 



Nevill further mentions a variety suhcatostoma from the Naga 

 Hills and Bhamo t, but he gives no description. 



The shell reproduced on plate 15, fig. G, of Conch. Ind. has the 

 last whorl descending for some distance below the periphery of 

 the penultimate whorl. Although similar forms frequently occur 

 I do not consider this typical, the normal form having the last 

 whorl abruptly deflexed in front. 



* J. A. S. B. xlvi, 1877, p. 17. 

 t Hand List, i, 1878, p. 74. 



