60 • HENRY CLIFDEN BDRNUP. 



features to a marked extent, it being even shorter than any 

 of the others, with a greater relative width. 



In my co-type of this variety and in the newly found 

 specimen the two parts of the labral tooth are more distant 

 than the original figure shows to have been the case in the 

 type^ so bringing them slightly nearer to the typical form of 

 E. columnella. The strengthening rib connecting the 

 columellar plait with the columellar lip is rather more tor- 

 tuous than in the type (of vitreola), but I do not consider 

 that an important feature. 



The following are the dimensions of the only four specimens 

 known : 



Height. Width. 



Type of E. vitreola (lost) . . 1-87 . 0-94 mm. 



Co-type in British Museum . . 1'82 . 0"92 „ 



„ „ Natal Museum . . I'Sl . 0-93 ,, 



Specimen collected lOthNov., 1913 1-76 . 0-92 „ 



The ratio of width to height in above varies from 50*27 to 

 52*27 per cent., while that of the measured specimens of 

 columnella, typical, from Dargle, varies from 42*31 to 49*20 

 per cent., and that of the higher shell from Lower Umkomaas 

 is 40*72 per cent. 



I am indebted to Messrs. E. A. Smith, Connolly, and Preston 

 for their views on the relationship of these two forms, 

 E. columnella, typical, and var. vitreola, arrived at 

 during a discussion over the type of the former and co-type 

 of the latter in the British Museum. It is at their suggestion, 

 in which I now fully concur, that I have retained the distinction 

 of the Hilton Road form under the name vitreola used in a 

 varietal sense. 



Although it will be seen that one of the Lower Umkomaas 

 specimens of E. columnella is even shorter than the type 

 of vitreola, it agrees in every respect except size with 

 columnella, typical, its relative proportions being about 

 equal to an average example of the Dargle specimens. The 

 most stunted example from Dargle approaches the proportions 

 of the variety vitreola, but can readily be distinguished 



