and Description of a new Genus, 239 



demonstrated. This is especially the case with the genus 

 Achatina, which had necessarily, in as far as its character was 

 merely founded on the truncated columella, to be again united 

 with Bulimus, as the animals, both as to their exterior as well 

 as their anatomical characters, are perfectly similar, and all 

 the intermediate forms may be followed, from the truncate 

 columella oi Achat, virginea to the beautiful round aperture of 

 BuL hcemastomus. But those species are excluded from this 

 reunion which Montfort comprised in his genus Polyphemus, 

 as these are not merely distinguished by the peculiar form 

 of the columella, but likewise by the bilobate snout of the 

 animal. 



I follow therefore in general the well sustained view of De- 

 shayes, who reunites the genera Achatina and Bulimus of La- 

 marck, and shows on anatomical grounds (Lam. viii. p. 14. 2de 

 edit.) that they cannot be comprised under Heliw, but I can- 

 not at all agree in the opinion expressed by the same ingenious 

 naturalist, that Clausilia and Pupa must likewise be combined. 

 I find, rather, no reason for separating Draparnaud^s genus 

 Pupa from Bulimus, In the European species described by 

 Draparnaud, there were, it is true, some constant character- 

 istics evident which appeared to justify this separation ; but 

 with how many species have we since then become acquainted, 

 which have shown the earlier generic characters to be insuf- 

 ficient, and have therefore been sometimes ascribed to the one, 

 sometimes to the other of these genera ! In fact, I know at pre- 

 sent not a single distinctive character between the two. The 

 animals are perfectly identical ; the form is in both cylindrical 

 or ovate ; and the oral edge disconnected. What therefore 

 is left ? The form of the aperture, or its folds and teeth ? The 

 form of the columella ? For all these characteristics the most 

 distinct forms of transition are afforded by Ferussac^s genus 

 Partula or Swainson's Achatinella, Are the teeth and folds 

 of the aperture to constitute the chief character, — which for 

 instance Menke seems to adopt, since he refers to the Pupce, 

 the long-known Bulimus Pupa ? But how^ many toothed spe- 

 cies do we not now refer without scruple to Bulimus, fol- 

 lowing the analogy with Helix, while at the same time we do 

 not class, for instance, Pupa obtusa among them ! In the ex- 



