MOLLUSCA or IjSTDIA. 343 



The Datjiling specimen figured is atypical one from the Blanford 

 collection. 



Original description : — "Testa aperU ximhilicata,depr€sso-turhinatn, 

 confertim striahda, striis nonnuUis ad suturcim elevatis, nitente, sub- 

 jH'Unci'fa, rufescenti-albida ; spira brevi, depresso-conoidea, apice 

 obtuso, svtura impressa ; anfractibvs 3| convewis, ultimo rotundato, 

 j'rofunde constricto, tubidum mediocrem gereyite, strictura crista 

 (rogusta elevata, intus cavo-sidcaia, pf'/-/s<OHi« expansum simulnnte, 

 ab apertara sepnrata ; apertura vi,v obliqua, subcircidari, peristomate 

 duplici, 7nargine columetlari leviter incrassato-rejlexo, dextrali valde 

 incrassato-porrecto, fortiter acutangidatim crispo-plicato, plicis 

 quinque aptrturani arctantibus, marginibus callo prominente angidato 

 junctis. 



"Operc. ? 



" Diam. major 2^, minor 2 : axis vix 2 mm, 



" Habitat in valle liungun. 



" The dimensions given are those of the largest of four specimens. 

 The strenuously vandyked plication of the incrassate edges of the 

 porrect dextral side of the peristome is a remarkable feature in this 

 minute species. It recalls the curious frill in Pterocyclos bilabiatus. 

 Sow., but in a more exaggerated guise, notwithstanding the small- 

 ness of the shell. The edges of the folds aretliickened and slightly 

 reflected. Its smaller size, sculpture, and wider umbilicus, and, 

 above all, the mode of constriction, prove that it is not an exagge- 

 rated form of crenidatus. The deceptive appearance of the ridge 

 or crest at first induced me to class the shell with Diorj/x; but a 

 closer investigation of the mode in which the ridge was attached to 

 the true peristome, and a view of the internal sulcus, revealed the 

 true position of the species." 



Altc^us PLECTOCHEiLFs, Bs., large var. (Plate CXXXIII. 

 figs. 3-3 c.) 



Damsang Peak, Western Bhutan (No. 1256 B.M. Coll.). 



Major diameter 3"75; alt. axis 1'6 mm. 



Of the typical specimen figured — 



Major diameter 3*20 ; alt. axis 1*5 mm. 



The operculum of this specimen is multispiral, smooth and black. 



Altc^us eechilaensis, n. sp. (Plate CXXXIV. figs. 2, ti a.) 

 No. 1252 B.M. Coll. 



LocnUty. Rcchila Peak, Daling District, on Sikhim-Bhuian 

 Frontier, 10,300 feet. 



Shell very openly umbilicated, depressedly conoid, covered with a 

 strong epidermis-^ scul pture : costidntion strong, very close and regular 

 on t(pper iuho7^h, still more so next sutural tube where 21 ribs can be 

 counted, the tube is rather short ; colour ochraceous with a green 

 tinge ; spire low, apex small ; suture well impressed ; whorls 4, 

 tumid, sides rounded, the distance from the constriction to the 

 aperture is not great and is crossed just behind it, by a well-defined 



PAET XII. 2 5 



