PLECTOPYLIS. 105 



Major diam. 15, minor 12 mm. ; alt. 5 mm. 



Hob. Burma: Thyet-Myo, Pegu; Kyengdwen Valley, N.W. 

 Burma (Ogle). 



In contour this species resembles Plectopylis perarcta, but the 

 shell is much larger. The parietal armature further connects it 

 with the species just named, but the palatal armature is more like 

 that of P. leiophis. 



The specimen figured, and one in the late Miss Linter's 

 collection, have the measurements given in the diagnosis, but my 

 second specimen measures only 12*5 millimetres in diameter. 

 Figs. 48 a-c show the shell in three different aspects, natural 

 size ; figs. 48 d-f are enlarged ; d shows the parietal and palatal 

 armatures from the posterior side ; /, the inside of the outer wall 

 with the palatal folds and denticles ; and e, the parietal wall with 

 its plate and folds. 



Two specimens collected by Ogle, in the Grodwin-Austen 

 collection, now in the British Museum, I refer to this species. 



96. Plectopylis shiroiensis, Godwin- Austen. 



Helix (Plectopylis} shiroiensis, Godwin- Austen, P. Z. S. 1874, p. 609, 



pi. 73, fig. 3 (shell and armature). 

 Helix shiroiensis. Hanley & Theobald. Conch. Ind. 1875, pi. 159, 



fig. 7. 

 Helix (Atopa (Plectopylis}} shiroiensis, Tryon, Man. Conch, ser. 2, 



iii, 1887, p. 163, pi. 35, fig. 90. 

 Plectopylis shiroiensis, Pilsbry, Man. Conch, ser. 2, ix, 1894, p. 145 ; 



Gude, Science Gossip, x. s. iii, 1896, p. 155, fig. 20 (shell and 



armature), torn. cit. p. 204. 

 Plectopylis (Ckersaecia) shiroiensis, Gude, op. cit. vi, 1899, p. 148. 



Original description: "Shell sinistral, openly umbilicated, 

 discoidal, thin, light brown, very finely striated. Apex flatly 

 convex ; suture slightly impressed ; umbilicus open and deep. 

 Whorls 6, the last rounded, sharply compressed on the lower part 

 behind the aperture and descending to it. Aperture broadly 

 lunate, very oblique ; peristome white, continuous, reflected. 

 Prom the centre of the parietal ridge completing the peristome a 

 lamella runs up that side of the whorl for three-sevenths of the 

 circumference towards the parietal plication, but does not join it ; 

 and here a short free horizontal lamella lies parallel to and below 

 it. The parietal vertical lamina is simple, with one short support 

 at the lower anterior end ; and below this is another, free, narrow, 

 horizontal lamella. Palatal teeth consist of 4, that are horizontal ; 

 the 4th is long, narrow, and curving inwards. Between the 3rd 

 and 4th is a vertical double-notched tooth, evidently a compound 

 and representative of two very oblique plicae." (Godwin- Austen.) 



Major diam. 8, minor 7 mm. ; alt. 4 mm. 



Hob. India: Shiroifurar, N.E. of Munipur. 



P. shiroiensis is allied to P. perarcta, and is likewise sinistral but 

 the shell is smaller, it is more raised in the spire and the last whorl 

 is deflected in front. There are also differences in the armature : 



