PLECIOPYLIS. 119 



hrachyplecta, I suspected that these shells would prove to pertiiin 

 to that species, and having obtained permission from Mr. Edgar 

 Smith, tfie late Assistant Keeper, to open one of the shells, I was 

 enabled to confirm my suspicion, for the armature proved to be 

 identical with that of P. hrachyplecta. One of these specimens is 

 shown in three different positions in figs. 57 a-c. It measures- 

 major diam. 22, minor 18-5 mm.; alt. 8 mm. 



IV. Section Plectoptlis, s. s., GucU. 



(Typical section of Benson.) 



Science Gossip, n. s. vi, 1899, p. 148. 



Sinistral, shell flattened. Palatal armature : one vertical plate 

 with three horizontal folds above, one below. 

 Type, Plectopylis hensoni, Gude. 



Range. Burma. 



105. Plectopylis ponsonbyi, Oodivin- Austen. 



Helix (Plectopylis) ponsonbyi, Godwin- Austen, P. Z. S. 1888, 



p. 24.3. 

 Plectopylis ponsotibyi, Pilsbry, Man. Conch, ser. 2, ix, 1894, p. 144, 



pi. 40, figs. 9-12 (shell and armature); Gude, Science Go.ssip. 



N. s. iii, 1896, p. 178, fig. 22 (shell and armature). 

 Plectopylis (s. s.) jJ07isonbyi, Gude, op. cit. vi, 1899, p. 148. 



Orif/inal description: — "Shell sinistral, widely umbilicated, 

 discoid, solid ; sculpture, wavy thread-like lines of growth ; colour 

 pale brown ; spire flat, 24 whorls at apex slightly raised above the 

 succeeding whorls ; suture very shallow ; whorls 7, closely wound 

 and flat ; aperture very oblique, descending, horizontally ovate ; 

 peristome thickened, reflected, the margins connected by a well- 

 developed ridge, and with slight notches at the inner angles. 



"Major diam. 17"5, minor 14, alt. 5 mm." (Godivin- Austen.) 



Hah. Upper Burma : Hlindet (Spratt). 



The shell is sinistral, disk-shaped, flattened above, with the apex 

 a little raised, composed of six and a half whorls, closely and 

 regularly coiled, rounded and gradually increasing ; it is regularly 

 and finely ribbed, and has the last whorl deflected in front ; the 

 parietal callus has a raised flexuous ridge, which is separate above 

 and below from the peristome. From the aperture may be dis- 

 cerned a short, free, slightly curved, parietal fold, which follows 

 the deflection of the last whorl (see tig. 58 a). The parietal 

 armature further consists of two strong vertical plates, the 

 posterior one of which is the longer of the two ; it gives off 

 posteriorly at the upper extremity a very short horizontal ridge, 

 and at the lower extremity another short, but stronger, ridge, 

 which descends obliquely ; the anterior plate is shorter but much 

 stronger and thicker than the posterior one, and it gives off two 



