108 HELICID^E. 



figured by me with P. perarcta, but as the second horizontal 

 lamella is joined to the vertical plate in P. pseudophis, and in my 

 specimen this lamella is quite free, as stated to be the case in 

 P. perarcta, it is evident that my shell is not P. pseudopliis ; more- 

 over, Mr. Blanford, in describing the shell, states that from the 

 centre of the curved ridge at the aperttire, " a lamella runs up the 

 whorl towards the parietal plication." It may, therefore, safely 

 be assumed that in the type specimen the horizontal lamella is 

 not interrupted, and the question arises whether the shell figured 

 by Lt.-Col. Godwin-Austen was perfect in having the hori- 

 zontal plate interrupted in the manner described. The palatal 

 armature is simple, and consists of four short, somewhat strong 

 horizontal folds, equidistant and parallel, with a smaller one above, 

 close to the suture, and two small ones in a line with each other 

 below, also near the suture (see figs. 50 b and c, the former figure 

 showing the posterior, and the latter the anterior ends of the 

 folds ; of the two bottom folds only one is visible in either 

 figure). 



98. Plectopylis brachydiscus, Godwin-Austen. 



Helix (Plectopylis) brachydiscus, Godwin-Austen, J. A. S. B. xlviii, 



1879, p. 2, pi. 1, fig. 1 (shell and parietal armature). 

 Helix (Atopa (Plectopylis)) brachy discus, Tryon, Man. Conch, ser. 2, 



iii, 1887, p. 162, pi. 36, figs. 32-34. 

 Plectopylis brachydiscus, Pilsbry, Man. Conch, ser. 2, ix, 1894, p. 146 ; 



Gude, Science Gossip, N. s. iii, 1896, p. 154, fig. 18 (shell and 



armature). 

 Plectopylis (Chersaecia] br achy discus, Gude, op. cit. vi, 1899, p. 148. 



Original description : " Shell dextral, umbilicus very open and 

 shallow, very discoid, rather strong, dull umber-brown, epidermis 

 thick with a cloth-like texture, finely and beautifully ribbed longi- 

 tudinally ; in young fresh shells the upper outer margin is closely 

 set with a strong regular epidermal fringe about '075 inches long. 

 Spire quite flat, approaching the concave in some specimens, the 

 apex itself having'a subpapillate form. Whorls 7, the last rather 

 flat on the side and angular above, descending at the aperture, 

 which is very oblique and oblate. Peristonie strongly reflected, 

 thickened, white, the margins connected by a well raised ridge, 

 notched above and below. A long horizontal lamella is given off 

 from the upper middle portion of this towards the vertical parietal 

 lamina, but only extends for 0*20 inches, then terminates, but at 

 15 inches is again developed, becoming thicker and higher as it 

 approaches the vertical lamina and ending just short of it, in this 

 respect being similar to P. perarcta. 



" The parietal vertical lamina is pointed above and gives off from 

 the lower basal end a short lamella towards the aperture, and a 

 very slight short thin, free lamina is to be seen just below the 

 vertical barriers. Palatal teeth simple, six, the 2nd, 3rd, 4th, and 

 5th are the best developed, the 1st and last are small, 2nd the 

 longest." (Godivin-Austen.) 



