PREFACE. XI 



19. The radical and epacmic forms of the Arietida? probably originated in the North- 

 eastern Alps, and migrated from thence southerly and westerly into Italy, and also in 

 another direction westerly into South Germany and the Cote-d'Or. In these last two 

 faunas new series of acmic forms arose by modification, and these and the paracmic 

 forms which seem to have arisen in the same basins flowed back into the Northeastern 

 Alps, and thence into Italy, during Bucklandian and later times. They were also dis- 

 tributed from these two basins to all others to the north and south of them in Central 

 Europe. The Northeastern Alps and the South German and Cote-d'Or basins constitute 

 a Zone of Autochthones for the Arietidse, and other faunas to the north and south of these 

 are what we have called Residual Faunas. 



The materials in the Museum of Comparative Zoology consist of various 

 collections made in England by Damon, Harder, and Wright; Boucault's 

 famous collection from the Cote-d'Or, containing several of D'Orbigny's types, 

 and in part named by him, or by direct comparison with bis collection; a 

 special and very large general collection, especially rich, however, in South 

 German species, purchased from Dr. Krantz; a valuable exchange from the 

 Museum at Stuttgardt named by Professor Fraas ; Professor Bronn's collection 

 labelled by him; a number of valuable species, principally from Belgium, from 

 L. de Koninck's collection; a similar lot presented by Prof. J. Marcou, from 

 various localities in Europe ; and others not sufficiently important to be men- 

 tioned here. 



ALPHEUS HYATT. 



Cambridge, April, 1889. 



