132 HBLICID.1;, 



doubted its occurrence there as much as that of P. bensoni, 

 recorded by Tryon in Proe. Asiat. Soc. 1870, p. 88. 



The peristome of P. cyclasjtis is thickened and reflexed and its 

 margins are united by a raised ridge ; the parietal callus bears 

 a short, strong, horizontal, entering fold, visible in its entirety 

 from the aperture (see fig. 65 a). The parietal armature consists 

 of a strong and very complicated ramified lamina, which ascends 

 obliquely from the side of the aperture near to the suture, where 

 it bifurcates, one arm — the upper one — ascending a little, then 

 proceeding horizontally and finally becomes attenuated ; the lower 

 and stronger one descends obliquely at an angle of 45° for about 

 half its length, then deflects almost vertically and gives off 

 posteriorly at its base a short strong support. The lower ex- 

 tremity of the main lamina also gives off anteriorly a short strong 

 support. Below the lamina is a free, short, horizontal fold. The 

 specimen shown with the outer wall removed in fig. 656 is not quite 

 mature, and it possesses the former barrier, which is evideatly 

 in course of absorption, as the second descending arm has almost 

 disappeared, and the lower free fold is also very slight. 



The palatal armature consists of five folds : the first thin, near 

 to and ahnost parallel with the upper suture ; the second, broad 

 and flexuous, descending obliquely posteriorly, half above and 

 half below the peripheral keel ; the third also broad and somewhat 

 crescent-shaped ; the fourth very strong, broad, and vertical, and 

 intercalating with the main stem and lower branch of the parietal 

 lamina; the fifth thin, horizontal, and parallel with the lower 

 suture. Fig. 65 c shows the parietal and palatal barriers from 

 the anterior side, while fig. 65 d exhibits the inside of the outer 

 wall with its palatal folds. At the base of the vertical palatal fold 

 on the right side — i. e. posteriorly — occurs a small denticle, 

 shown erroneously on the left side. Fig. 65 a shows a mature 

 specimen, and is of natural size ; the other figures are all magnified. 

 Both specimens are from Moulmain and are in Mr. Ponsonby's 

 collection. The mature shell measures ; major diam. 17, minor 

 14-5, alt. 7 mm. 



113. Plectopylis karenorum, Blanford. 



Helix {Plectopylis) karenorum, Blanford, J. A. S. B. xxxiv, 1865, 



p. 73 ; Godwin-Austen, P. Z. S. 1874, pi. 74, fig. 5 (shell and 



armature). 

 Kelix karenorum, Pfeitfer, Novit. Conch, ser. 1. iii, 1869, p. 503, 



pi. 1U8, figs. 16-18; Ilanley & Theobald, Conch. Ind. 1870, 



pi. 13, fig. 6. 

 Helix {Atopa (Plecfopi/lis)) karenorum, Tryon, Man, Conch, ser. 2, 



iii, 1887, p. 164, pi. 35, figs. 96-100. 

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



Gude, Science Gossip, n. s. iii, 1887, p. 244, fig. 35. 

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



Origincd description: — "Shell sinistrorse, very widely umbili- 

 cated, discoid, flat above, solid, white, with rather irregular oblique 



