THi] CARNIVOROUS SLUGS OF SOUTH AFRICA. 



255 



group, for wliich we may adopt Pilsbry's term Agnatlio- 

 niorphaJ Whether the purely American family Circi- 

 iiariida3 should also be placed in this group I am unable to 

 say. Pilsbry considers that it is allied to the Streptaxidas, 

 but Simroth believes it to be related to the Zonitidfe. There 

 are possible objections to both these views, but as I have not 

 had an opportunity of examining any members of the Circi- 

 nariidie myself, I will refrain from expressing an opinion 

 upon its affinities. 



Thus the carnivorous snails and slugs should probably be 

 classified as follows : 



JTestacellid^e. 

 l01eacinida3. 



S i u" m u !• e t h r a - 



A g n a t h a 

 Agnathomorp 



r Aperidas 

 r p h a J 



A.ulacopoda 

 or 

 ^ X y g n a t h a 



Rhytididas. 



Streptaxid^. 



Circinariida3. 

 ' Daudebardiina3. 



( Z o n i t i n a3 ) . 



Plutoniina;. 



(Vitrininte). 



T r i g o n o c h 1 a m i n a3, 



(ParmaceUince, etc.). 

 Ditreinata ..... Rathouisiidee. 



While it is hoped that this classification rests on a firmer 

 basis than previous attempts of a similar nature, it must be 

 remembered that we still know very little of the comparative 

 anatomy of the carnivorous suails and slugs. To give a single 

 example: about a hundred species of the genus Ennea 

 are known to occur in South Africa alone, and I believe that 

 I am right in saying that not a single feature of the anatomy 

 of any of these species has been described. As we are equally 

 ignorant of the anatomy of many other carnivorous genera, it 

 is at present impossible to do more than give a rough outline 

 of their probable affinities. Let us hope that the time will 

 soon come when collectors of shells will cease to throw away 

 ' ' Proc. Acad. Nat. Sci. Phila.,' 1900, p. 564. 



