ON SOUTH AFEICAN ENNEiE. 51' 



different, does not specify in what respects they differ. 

 Melvill and Ponsonby's figure of Ennea thelodonta^ is 

 confusing, showing at the same time, to a great extent, a side 

 view of the spire, and a front view of the apertvire ; besides, 

 the detail is faulty. I therefore present a new figure of their 

 species (fig. 37), for comparison with that of consobrina. 

 It will be seen from these that the likeness between the two 

 species, though striking, is only superficial, the detail of the 

 labral tooth and columellar plait in each being of quite a 

 distinct character. In consobrina the large labral pi'ocess 

 bears on the inner edge two distinct, little in-running plaits : 

 in thelodonta a somewhat similar, but smaller, process is 

 merely slightly divided into two lobes. In consobrina the 

 deep-seated columellar plait is strengthened by a transverse 

 rib; in thelodonta it is merely drawn forward at the lower, 

 inner corner, into a rounded point. In neither case does it 

 seem likely that the difference between these processes is the 

 result of the direct evolution of one form from the other, for 

 they seem to be constructed on different plans; therefoi-e I 

 consider the two species quite distinct. In addition, there is, 

 as pointed out by Ancey, the difference in size and number 

 of whorls, which is very considerable, though probably not 

 quite so great as would appear from a comparison of the 

 descriptions; for, while Ancey describes his shell as 8 mm. 

 high and 4 mm. wide, or, as he says, twice as large as thelo- 

 donta, Avhich is described as 4 mm. high and 2 mm. wide, 

 my measurement of Ancey^s type makes it 8 mm. high and 

 3*7 mm. wide, while my two specimens of thelodonta 

 measure as follows : 



Height X width, 4-87 x '2-26, 4-25 x 2-15 mm. (fig. 37). 



These specimens were collected at Port Elizabeth by Mr. 

 -T. Farquhar. 



Other specimeus of E. consobrina examined by me 

 measure as hereunder : 



In my collection at the Natal Museum, 7*75 x 4'0 ; in 

 collection of J. H. Ponsonby, 7-75 x 3-67, 7-75 x 3-67 mm. 



' ' Ann. and Mag. Nat. Hist..' vol. ix (1892). pi. vi. fig. 4. 



