MOLLUSCAN AFFINITIES 271 



Haiti and Mexico. The genus Gaeotis is quite confined to 

 Portorico, while Amphibulima is limited to the Lesser 

 Antilles.* 



All these studies yield the samp fundamental results, 

 namely, the presence within the Antillean area of an ex- 

 tremely ancient stock distantly related to that of Central 

 America and northern South America. After this fauna 

 had developed to some extent, a widespread destruction 

 apparently took place, due probably to submergence, fol- 

 lowed by a reimmigration from the south and west. A 

 more precise knowledge, however, of the minor physical 

 changes which the "West Indian islands have undergone 

 can be acquired when we compare the results derived 

 from the sedentary or slowly moving mollusks with those 

 drawn from the more active members of the fauna. But 

 there is one more element of importance in the Antillean 

 molluscan farma which has not yet been considered. It 

 is especially in view of the remarks I made in the ninth 

 chapter, on the striking relationship of the south-western 

 American fauna to that of Europe, that I wish to direct par- 

 ticular attention to the European affinities of the Antillean 

 fauna. 



I think it was Dr. Kohelt f who first animadverted on the 

 resemblance between the European molluscan fauna and that 

 of the Antilles and Central America. At first sight, as he 

 remarks, the two faunas seem to be as distinct as any disciple 

 of the principle of multiple centres of creation could wish. 

 After a careful study, however, we certainly perceive distinct 

 traces of relationship. The carnivorous snail Glandina, which 

 is represented in the Mediterranean region of Europe by a 

 single .species, has its headquarters in the Antilles and in 

 the surrounding States. It cannot be looked upon as a recent 

 introduction to Europe, because its discontinuous range be- 

 between the Caucasus and Algeria is altogether opposed to any 

 such supposition. Several species of Glandina, moreover, 

 occur in French and English Eocene, Oligocene and Miocene 

 deposits, some of them being almost identical with still 



* Pilsbry, H. A., "Manual of Conohology," Vols. X.— XII. 

 f Eobelt, W., " Verhaltniss d. Europaisclien LandmoUuskenfauna, &c.," 

 p. 145—148. 



