THILALANKA. 2',i 



tenuis, pallide cornea, striatiila ; spira conoidea, apice obtusa, 

 sutura inipressa. Ant'r. G aiigusti, convexi, ultimiis baud descen- 

 dens, subtus rotundatus. Apertura subverticalis, rotundato 

 lunaris ; peristoma simplex, raarginibus distantibus, columellari 

 reflexiusculo. 



" Diam. maj. 2|, miu. 2^, alt. 1| mm." {Blanford.) 

 Hah. India: Nilgiri Hills, Pykara and Neddiwuttora. 



4u. Philalanka thwaitesi, Pfciffer. 



Helix thwaitesi, I'feilier, P. Z. S. ISoS, p. li-"); Reeve, Conch. Icon. 



vii, 18.54, pi. 191, fig. 13.36; Hanley & Theobald, Conch. Ind, 



187.J, pi. li>S, lijrs. 7-10. 

 Helix (Microcijtitis) thwaitesi, Pfeiffer, ^lalak. Bliitt. ii, 1850, 



p. 123. 

 Nanina {Microo/s/is) thwditesi, Tryou, Man. Conch, ser. 2, ii, 1886, 



p. 118, pi. 39," fig. 5. 

 Microci/stis nuicara, Jousseaurae, Mem. Soc. Zool. France, vii, 1894, 



p. 27.3. 

 Philalanka thwaitesi, Godwin-Austen, Moll. India, ii, 1907, p. 193, 



pi. 112, fig. 1 (jaw & radula). 



Ofiginal description: — "T. aperte perforata, convexo-depressa, 

 si riatula nitida, cereo-hvalina ; spira breviter conoidea, obtusula ; 

 sutura profunda, submargiuata ; anfr. 6| convexi, arete convoluti, 

 iiltimus non descendens, basi iiiHatus ; apertura verticalis, lunaris ; 

 perist. rectum, acutum, margine cohimellari aicuatim oblique 

 dt'sceudente, ad perforationeni vix dilatato. 



" Diam. raaj. o, miu. 4.|, alt. 3 mill." {Pfeiffer.) 



Hah. Ceylon (Thwaites) ; Nuwara-EIiya (^'w»o«) ; Ambagamu\va 

 (CoUeti). 



Under a strong lens the shell is seen to be densely covered with 

 si)iral stria?. Mr. E. Ii. Sykes established the fact (Proc. Malac. 

 Soc. London, iii, 1898, ]).6o)xha.t 3Iicrocifstis nnwara, Jousseaume, 

 and the present species are identical. Jousseaume, in fact, based 

 his species upon the figure of tjiwaiiesi in Conch. Icon., which 

 was drawn from Pfeiffer's type. 



lit.-Col. Godvxin-Austen investigated the anatomy and describes 

 the genitalia, but he gives no figures. 



\'ar. suavis, Jonsseauine. 



Microcystis suavis, Jousseaume, Mem. Soc. Zool. France, vii, 1894, 

 p. 273, pi. 4, fig. 3 ; Collett, J. A. S. B. Cevlon Branch, xv, 1897 

 (1898), p, 12. _ 



Microcystis thwaitesi, var. suavis, Sykes, Proc. Malac. Soc. London, 

 iii, 1898, p. 65. 



Differs from the typical form in having a slightly more depressed 

 spire, a somewliat larger umbilicus, and in the mouth being some- 

 what different in shape. 



Hah. Ceylon : Nuwara Eliya {Simon); Ambaganmwa (Collett). 



