The Non-Marine Mollusca of Portuguese East Africa. 167 



tioned, the chief points of distinction being that their central teeth are even 

 narrower, and the whole radula is longer, the number of transverse rows 

 being 179 in one specimen and 187 in the other, whereas the radular formula 

 of the Rikatla example is (88+1 + 89) X 143 and that of the Macequece 

 specimen (77+ 1 + 79) X 159. These radular differences between A. pantkera 

 and A. immaculata are not, however, very great, and no marked differences 

 were found in the other organs ; it therefore seems not impossible that 

 immaculata may eventually prove to be merely a subspecies of A. panther a 

 in which the shell and radula have become slightly modified in response 

 to the somewhat different climate and vegetation of the district 

 in which it occurs ; both species are remarkable for their roseate 

 columella. 



Two examples from Rikatla in the Kimberley Museum show a beautiful 

 variation in colour that is rare in this species. The early whorls are almost 

 colourless, deepening at the 5th into pale bufi ; in an immature shell, 

 65x40 mm., possessing 6 whorls and showing marked angulation at the 

 periphery, there are pale rufous flames some distance apart and a few 

 blotches somewhat corresponding to the darker markings of the typical 

 form. In the larger shell, 95 X 56 mm. with 7 whorls, the streaks have 

 grown nearer together, giving the shell the appearance of having been 

 varnished pale yellow and combed over with a coarse comb. 



Achatina immaculata (Lam.), 1821. 



1851. Achatina immaculata, Lam., Desh., Hist. nat. An. s. Vert., II, 2, 

 p. 158, pi. 127, figs. 1-2. D.F. 



Hah. L. Marques. Inhambane (Gibbons) ; Delagoa Bay (fide Pfeifier). 



In view of my note on A. panthera, it may be a little doubtful 

 whether these records should not refer to that, rather than to the present 

 species. 



The Transvaal form known as immaculata is very constant in shape, but 

 variable in colour! The apex is small and acute, and the whorls, about 

 7h in number, increase regularly and somewhat rapidly, the last being 

 nearly f of the entire length. Immature shells are sometimes almost white, 

 with rare pale rufous streaks ; mature examples all shades from pale buff 

 to dull chestnut, sometimes with darker streaks and blotches ; columella, 

 paries, and peristome bright rose-red or pink, often showing round the 

 outside of the peristome. 



It will be observed that some of these colour-schemes practically merge 

 in that of A. panthera, and it is almost impossible, in such cases, to separate 

 the species. 



