T, Bland on the Geographical Distribution of Mollusca. 393 



They have also a determinate geographical distribution. The 

 facts on these subjects are even more nnmerous than those which 

 are expanded over the whole temperate regions of North America. 

 In this respect, therefore, the island is a miniature continent. 

 Probably the same is true of each of the larger Ar)tilles." 



We now refer to the work of the late Dr. Binney, on " The 

 Terrestrial Air-Breathing Mollusks of the United States,''' [Bos- 

 ton, 1851,) published, since his death, under the able editorship 

 of Dr. Gould. This work is indeed an imperishable record of 

 ,the talents and love of science of its author, — a noble legacy to 

 his country. 



Dr. Binney highly appreciated the value of a study of the 

 geographical distribution of shells. His first volume contains 

 some interesting chapters relating to the subject, — we refer espe- 

 cially to the eighth. In that, and other parts of the book, various 

 comparative tables of the habitats of shells are introduced, and the 

 value of a complete series, including especially those of limited 

 districts which present strongly marked topographical or climatal 

 peculiarities, is pointed out. 



The ninth chapter is devoted to •' Geological relations." The 

 most important inference, with respect to the geological history 

 of this continent, deduced by Dr. Binney from his consideration 

 of its fossil terrestrial shells is thus stated : — 



" That our existing species of land Mollusks were living at a 

 period which, though recent in a geological sense, was anterior to 

 the last geological revolution, when the surface of this portion of 

 the earth was brought to its present condition, and to the exis- 

 tence of the higher orders of animals which now inhabit it, and 

 even to that of the extinct mammalians which are known only 

 by their gigantic remains." — p. 185. 



Stimpson, in his ^^ Shells of New England,^^ (Boston, 1851,) 

 displays the growing interest attached to the subject before us, in 

 his notes on the geographical, and bathymetrical, or horizontal 

 and vertical range of each species. The observations of this au- 

 thor on the anatomy of the animals of many species of shells are 

 very valuable. 



The remarks of Dr. Gould in his " Introduction to the Mol- 

 lusca of the United States Exploring Expedition,''^ {December, 

 1851,) are eminently worthy of notice, as the following extracts 

 will abundantly prove. 



" The doctrine of distinct zoological regions evidently apper- 

 tains to the Mollusks, and is well illustrated by them. In nearly 

 every work, containing any considerable catalogue of shells, the 

 same species will be found quoted as being found in widely dis- 

 tant regions, in different oceans, and even on opposite sides of the 

 globe. The many thousand localities carefully noted on the 

 records of the Expedition go to prove beyond dispute, that no 

 such random or wide-spread distribution obtains." — p. ix. 



