MOLLLSCA on INDIA. 169 



three whorls, enlarged about 20 diameters. This gives the coil its 

 size exactly, and tracings can be placed one upon the other for 

 comparison. 



Macrochlamys saxhilaensis, n. sp. (Plate CVI, figs. 4-4 c.) 



Locality. Richila Peak, Bhutan frontier, 7 specimens {Wm. 

 Robert) . 



Shell (fig. 4) globosely conoid, translucent, delicate structure, 

 narrowly umbilicated ; sculpture confined to some very delicate 

 fine longitudinal striation near the suture, which dies out, and the 

 rest is perfectly smooth, crossed transversely by wavy furrows ; 

 colour pale ochraceous ; spire moderately high, conoid ; suture 

 moderately deep ; whorls 6, gradually increasing ; aperture widely 

 lunate, oblique ; peristome very seldom quite perfect. 



Size : maj. diam. 13'5, min. 12-0 ; alt. axis 6-5 mm. 



This shell, which has very much the coloration of M. sequax, 

 differs altogether in form. It belongs to a group very similar one 

 to the other, very common, and very variable with locality. I 

 cannot exactly match it with any Khasi Hill species. 



Animal. Colour throughout pale ; no markings, only a slight 

 grey tinge near the head. The withdrawn tentacles are very 

 black, and in life probably show as dark lines on the neck ; pallial 

 margin finely streaked. The shell-lobes and extremity of foot as in 

 M. sequius from Damsang ; and the radula is of the same type 

 exactly : 



+ 31 . 2 . 11 . 1 . 11 . 2 . 31 + 

 + 44 . 1 . 44 + 



The smaller teeth near the margin would add another 10 or 15 to 

 the above, or about 90 in the row. 



The jaw (fig. 4 c) is well arched, Avith a large central projection. 



The visceral sac is closely mottled and shows dark inside the 

 shell. 



The penis (figs. 4 a, 4 b) is quite different from that of sequax 

 (fig. 1 a) ; the caecum, instead of being closely coiled, is free, 

 similar in size and length to the kalk-sac ; the epijjhallus is very 

 short, and just below the retractor muscle there is a globose 

 enlargement of the penis-tube. The amatorial organ is long. In 

 the free caecum the male organ may be compared to the similar 

 character found in M. ricliilaensis. 



This species was also obtained in the Risett chu Valley, and is 

 represented by eight sjjecimens, some of which are rather flatter 

 in the spire than the type. Three specimens are from Rissom 

 Peak. 



Perhaps the most interesting point brought to light by the 

 examination of the Sikkim land-shells is the presence in three of 

 them, viz. M. ricliilaensis *, M. zemoensis, and M, sathilaensis, of a 



* For details, vide p. 155, 



