THE CARNIVOROUS SLUGS OF SOUTH AFRICA. 247 



of the foot in Apera and Natalina ; they are, however, very 

 inconstant, and instead of being parallel they diverge for- 

 wards and seldom extend for moi*e than half the length of the 

 animal. Authorities diifer with regard to the foot-sole of 

 Testacella: Plate states that longitudinal grooves are 

 present; Taylor^ says that they are absent ; Pfeffer- found 

 them only in the anterior two-thirds of the foot-sole ; 

 Simroth ^ saw traces of them towards the hind end of the foot 

 in a few individuals only. I have examined the foot-sole in 

 about a dozen examples of Testacella maugei from various 

 localities, and I found that about half the specimens showed 

 no trace of longitudinal grooves, Avhile in the others the 

 grooves were present, but they were much less conspicuous 

 than in Daudebardia, etc., and diverged forwards from the 

 hind end as in Apera. In other words, the grooves on the 

 foot -sole of Testacella, instead of being constant and 

 approximately parallel, as in the other European carnivorous 

 slugs, are divergent and very inconstant. We see, then, that 

 the evidence of the various dermal grooves of Testacella is 

 against Pilsbry's hypothesis instead of in favour of it. 



Turning now to the evidence aiforded by the length of the 

 cerebral commissure, we find that while in Daudebardia 

 and the Tr i go noch laminae the commissure is moderately 

 long, in Testacella, as in the OleacinidiTe, Streptaxidas, 

 Ehytididae, and Aperida?, the commissure is quite short, 

 and the cei'ebral ganglia are in consequence close together. 

 This fact was cleai'ly stated by Strebel'^ thirty-six years ago, 

 and has been abundantly confirmed by subsequent investiga- 

 tions. It is therefore evident that the only features upon 

 which Pilsbry seems to base his theory of the affinities of 

 Testacella are found on examination to support the contrary 

 hypothesis. 



' ' Monog. L. and F.-W. Mollusca Brit. Isles,' 1902, vol. ii, p. 2. 

 2 Op. cit., p. 75. 



•* ' Nova Acta Acad. Cses. Leop. -Carol. Germ. Nat. Cur..' 1891. vol. 

 Ivi, p. 241. 



* Op. cit., vol. iii, p. 5. 



