138 HELICID2E. 



sinuous raised ridge on the parietal wall at the aperture connects 

 the margins of the peristome; at the junctions above and below, 

 however, there are slight notches. The armature is similar in 

 most respects to that of P. repercussa, but it is less solid and 

 heavy; the lower arm of the bifurcation on the parietal wall is 

 J onger than the upper, and the thin free horizontal fold near the 

 lower suture is not united to the ridge at the aperture and does 

 not proceed beyond the lower arm of the bifurcation as is the case 

 in P. repercussa. The upper fold of the palatal armature is much 

 shorter than in that species, terminating posteriorly at the same 

 point as the shorter upper arm of the parietal bifurcation ; the 

 second and fifth horizontal palatal folds are much shorter an- 

 teriorly than in P. repercussa ; while the vertical palatal lamina 

 (the fourth) is broader, but less stout and less inclined towards 

 the aperture than in that species. 



The specimen shown in figs. 69 d and e is from Moulmain and 

 is in my collection. It measures : major diam. 28, minor 22, 

 alt. 7'5 mm. Pig. 69/ shows the posterior aspect of its parietal 

 and palatal armature. Pigs. 69 a-c are reproduced from photo- 

 graphs (natural size) of Gould's types in the New York State 

 Museum, Dr. Bagg having supplied the following notes : " Helix 

 anguina, Gould. Catalogue number, 251 ; Original number, 

 A 558. The shell is somewhat banded by brownish and white 

 alternating, but not in all specimens." 



116. Plectopylis bensoni, Gude, nom. mut. 



Helix achatina (Gray), Pfeiffer, Zeits. Malak. ii, 1845, p. 86 ; Benson, 

 A. M. N. H. ser. 3, iv, 1859, p. 59 ; Kobelt, 111. Conch. Buch, 

 ii, 1879, pi. 71, fig. 9. 



Helix (Plectopylis) achatina, Benson, A. M. N. H. ser. 3, v, 1860, 

 pp. 244, 245 ; Nevill, Hand List, i, 1878, p. 71 ; Godwin- Austen, 

 P.Z.S. 1874, pi. 74, fig. 6 (armature); J.A.S.B. Ixiv, 1895, 

 pi. 7, fig. 5 (animal) ; Tapparone Canefri, Ann. Mus. Civ. Geneva, 

 ser. 2, vii, 1889, p. 47. 



Helix (Atopa (Plectopylis)} achatina, Try on, Man. Conch, ser. 2, 

 iii, 1887, p. 165, pi. 35, figs. 3-5, 7, 8. 



Plectopylis achatina, Stoliczka, J. A. S. B. xl, 1871, p. 221, pi. 15, 

 figs. 1-3 (anatomy) ; Pilsbry, Man. Conch, ser. 2, ix, 1894, p. 145 ; 

 Gude, Science Gossip, N. s. v, 1898, p. 114, figs. 80-82. 



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



Original description : " T. sinistrorsa, latissima umbilicata, 

 depressissima, discoidea, laevigata, superne rufa, albido rnaculata 

 et flammata, basi pallida; spira plana, medio vix elevatiuscula ; 

 anfr. 6| subplanulati, ultimus a latere subcompressus, antice 

 subito deflexus ; apertura subhorizontalis, oblongo-subcircularis ; 

 perist. fusculum, undique expansion et reflexum, marginibus 

 lamina prominente, lamellam profun.de intrantem emittente 

 junctis. 



" Diam. major. 31, minor 24, alt. 8| mill." (Pfeiffer.) 



