COOKE : ON THE GENUS CLAUSILIA. 267 



view will regard Laminifera as a possible link between Nenia and the 

 Clausilias of the Old World. It is conceivable that the now existing 

 species of Laminifera represent the relics of a group whose progenitors 

 were not only more widely distributed in Europe, but also succeeded 

 in emigrating, by what route we are not in a position to say, into the 

 region we now call South America. There can be little doubt that 

 instances occur of similar survivals, which have, by taking refuge, as 

 it were, in mountain fastnesses, victoriously defied (to use Boettger's 

 phrase) the attacks of younger and better organized groups. In this 

 connexion may be mentioned the group Olympia (Mt. Olympus), 

 Serrulina (Armenia and North Persia, and fossil from the Miocene of 

 Bohemia and Silesia), Alopia (Carpathians), 'and j}0?,s\\i\y Macroptydiia 

 (Abyssinia). 



The only other living group which shows a production of the last 

 whorl, with a continuous peristome, is Garnieria, from Indo-China, 

 a sinistral group, in which the mouth is set, as in Nenia, exactly 

 in a line with the axis of the spire. The general facies of the group 

 now inhabiting Madeira [Boettgeria) is not markedly akin to 

 Laminifera, and therefore cannot be cited as supporting a theory of 

 Atlantidean migration. Professor Gwatkin assures me that the 

 radulae of the few species of Nenia which he has been able to examine 

 are of the same general type as that of the Palaearctic Claiisilice. 

 Further light may be thrown by a detailed examination of the 

 clausilium. 



List of the principal "Works quoted. 



1. Benoit, L. Nuovo Catalogo delle Conchiglie terrestre e fluviatili della 



Sicilia ; Messina, 1881. 



2. Boettger, C. E. " Die Molluskenfauna der preussischen Eheinprovinz " : 



Arch. Naturges., Ixxviii, A. 8, 149-310, 1912. 



3. Boettger, 0. " Clausilienstudien" : PalEeontographica, 3rd Supplement, 



1877. 



4. " Monographic der Clausiliensection Albi7iaria, v. Vest " : Novitat. 



Conch., i (Extra-abdr.) ; Cassel, 1878. 



5. " Beitrag zu einem Katalog der innerhalb der Granzen des 



Russischen Reichs vorkommenden Vertreter der Landscbneckengattung 

 Clausilia " : Bull. Imp. Ac. Sc. St. Petersb., xxv, cols. 163-90, 1879. 



6. ' ' Zur Molluskenfauna der russischen Gouvernements Poltawa, Perm, 



und Orenburg" : Nachr. Deut. Malak. Ges., xxi, 120-33, 1889. 



7. " Zur Molluskenfauna des russischen Gouvernements Perm und 



des Gebietes sitdostlich von Orenburg " : Nachr. Deut. Malak. Ges., 

 xxii, 161-73, 1890. 



8. "Die Binnenmollusken Transkaspiens und Chorassans " : in 



Radde, Expedition nach Transkaspien, i, Zool., 1890. 



9. " Verzeichniss der . . . aus Griecbenland . . . mitgebrachten 



Vertreter der Landscbneckengattung Clausilia, Drp. " : Abb. 

 Senckenb. Ges., xvi, 31-68, 1891. 



10. " Neue iVenia : Bestimmungsschliissel und Literaturnachweise fiir 



die bis jetzt bekannten i^^enia- Arten " : Nachr. Deut. Malak. Ges., xxi, 

 162-83, 1909. 



11. and Schmacker, B. "Description of new Chinese ClausilicB ": 



Proc. Malac. Soc, i, 100-17, 1895. 



12. Bourguignat, J. R. " Histoire des Clausilies de France vivantes et 



fossiles " : Ann. Sci. Nat., 1877, No. 10. 



