24 



41. Philalanka depressa, Preston. 



Microcystis thwattesi, var. depressa, Preston, Rec. Ind. Mus. iii, 

 1909* p. 135, pi. 22, fig. 6. 



Shell depressed-conoid, almost lenticular, pale corneous, trans- 

 lucent, shining, very finely striated and with excessively minute 

 spirals ; spire much depressed, suture deep. Whorls 4|, strongly 

 convex, closely wound. Aperture vertical, reniform ; peristome 

 acute, upper margin ascending at first, outer and basal evenly 

 arcu;ite, columeliar slightly dilated, vertical. 



Diam. 3*5, alt. 2 mm. 



Hab. Ceylon : Uda Pussellawa (Preston). 



Mr. Preston considers this form a variety of thivaitesi, stating 

 that, except in the depressed spire, it appears to be normal. The 

 figure certainly bears out this view, but it must have been very 

 badly drawn. A specimen, received by me from the author, 

 differs from thwaitesi in several important respects, and the fore- 

 going description has been drawn up from it. The shell is much 

 more depressed, being almost lenticular ; the whorls are much 

 more convex above, the umbilicus is much wider, distinctly showine 

 all the whorls ; on the other hand, the region round the umbilicus 

 is not excavated as in thwaitesi, and the mouth is also different, 

 being reniform, not lunate. The whole shell has, in fact, a totally 

 different aspect, and I have no hesitation in according it specific 

 rank. 



42. Philalanka circumsculpta, Sylces. 



Microcystis thwaitesi (non Pfeiffer), Jousseaume, Mem. Soc. Zool. 



France, vii, 1894, p. 272. 

 Macrochlamys ? circumsculpta, Sykes, Proc. Malac. Soc. London, ii, 



1897, p. 23o, pi. 16, tigs. 3 & 4 ; op. cit. iii, 1898, p. 65. 

 Philalanka circumsculpta, Godwin - Austen, Moll. Ind. ii, 1907, 



p. 194. 



Original description : " Testa perforata, convexo - depressa, 

 nitidn, cereo-hyalina ; spira breviter conoidea, apice obtusa ; 

 sutura impressa ; anfr. 5, convexi, arteconvoluti, obsolete spiraliter 

 lirati, ultimus non desceridens, basi inflatus; apertura lunaris ; 

 peristoma rectum, acutum, margine columellari ad perforationem 

 dilatato, subreflexo. 



" Diam. max. 5, min. 4-7 mm. ; alt. 3 mm." (SyTces.) 



Hab. Ceylon : WataualafCoZZe^) ; Nuvvara-Eliya (Simon). 



11 This species is nearly related to the Helix thwaitesi of Pfeiffer 

 (which is also obsoletely spirally lirate), but may be at once dis- 

 tinguished by the fact that its breadth is greater in proportion to 

 the number of whorls. The umbilicus is also slightlv smaller in 

 the present species, the spire is not so much raised in proportion, 

 and the nucleus is larger. The sculpture is stronger thun in 

 H. thwaitesi, and a few of the stronger lines of growth intersect 

 the revolving lirae, thus giving the shell a decussated appearance 

 under a lens." 



