PLECTOPYHS. 83 



descending fold, a little more oblique than the previous one ; and 

 sixthly, a very short and narrow horizontal fold near the lower 

 suture, situate below the space between the two preceding series. 

 Fig. 31 a is from one of the type specimens ; it measures, major 

 diameter, 9 millimetres ; minor diameter, 8 millimetres ; axis, 

 5 millimetres. Two other of these specimens measure 8*5 milli- 

 metres, and one 8 millimetres in diameter. Fig. 31 6, showing the 

 parietal wall with its armature by itself, and fig. 31 c, showing the 

 inside of the outer wall with its palatal folds, are from a spe- 

 cimen in my collection, from the Khasi Hills ; it measures 

 major diameter, 8*5; minor diameter, 7*25; axis, 4'5 millim. 

 The specimens of this form range from 8 to 9 millimetres in 

 diameter. 



Var. tricarinata, Gude. 



Plectopylis plectostoma, var. tricarinata, Glide. Science Gossip, N. a. 

 iii, 1897, p. 275 ; ibid., Journ, Malac. vi, 1897, p. 45, fig. 2. 



Differs from the type in being larger and more conical, in 

 having the periphery acutely keeled, and in having three raised 

 ridges between the periphery and the suture, revolving as far as 

 the fourth whorl. 



Diam. major 10, minor 9 mm. ; axis 6 mm. 



Hab. Bengal (Benson) ; Khasi Hills (H. F. Blanford). 



This variety is based on two specimens from the Benson 

 collection, labelled Bengal. The shell is shown enlarged in 



Fig. 32. Plectopylis plectostoma, var. tricarinata. 



fig. 32 a, while a portion of the last whorl, more enlarged, is 

 depicted in fig. 32 b. The Blanford collection now in the 

 British Museum also contains a specimen collected in the Khasi 

 Hills by the late H. F. Blanford. 



Var. exserta, Gude. 



Plectopylis plectostoma, var. exserta, Gude, Journ. Malac. viii, 1901 > 

 p. 49, fig. 5. 



Differs from the type in the peripheral keel being exserted. 

 The shell is also larger and more solid. More than thirty 

 specimens were received from a native collector. 



G2 



