THE NAUTILUS. 93 



LAND AND FRESH-WATER MOLLUSKS OF ALASKA AND ADJOIN- 

 ING REGIONS. By William H. Ball (vol. xiii of the Harriman 

 Alaska Expedition. The scope of this handsomely printed volume 

 of 171 + xii pp. is as follows : " The first object of this work is to 

 sum up the known molluscan fauna of the land and fresh waters of 

 Alaska. This has involved an examination not only of the species 

 obtained within the political boundaries of Alaska, but also those of 

 the adjacent regions to the west, east and south. The result is that, 

 for North America north of latitude 49 north, the work includes a 

 summary of our present knowledge of the mollusks, deduced in part 

 from the literature and in larger part from material actually exam- 

 ined. To this is added a briefer examination of the mollusk fauna 

 of the adjacent parts of eastern Siberia, which has to some extent 

 modified that of Alaska." 



Four faunas are recognized as influencing the Alaskan non-marine 

 mollusks : that of northern Canada, that of the northern Pacific 

 States of the U. S., and in a much less degree the fauna of north- 

 eastern Asia, and the Holarctic group of mollusks common to all 

 northern regions. From all sources, 65 species of land and fresh- 

 water mollusks are known from within the boundaries of Alaska. 

 In the list of species, references are restricted to original descriptions 

 and records of occurrence in the boreal region. Most of the species 

 are illustrated by text figures from the works of Binney and Prime, 

 a feature largely adding to the usefulness and attractiveness of the 

 work. Besides records from the literature, a great mass of new data 

 is presented. Frequently vast areas are added to the known distri- 

 bution of our species, supplying numerous localities where before 

 only isolated or frequently doubtful records existed. The amount 

 of new information is so great that no attempt to condense it here 

 would be satisfactory. A few interesting points about particular 

 species may be mentioned. Epiphragmophora fidelis and Polygyra 

 columbiana are the only large Helices which actually reach Alaska, 

 though a good many others are recorded from north of 49. The 

 figure of P. monodon (p. 26) represents P. m. fraterna. It is re- 

 ported from Moose Factory, James Bay. Vertigo arctica Wallenb. 

 is given as from Port Clarence, collected by the Vega Expedition, 

 and V. krauseana Reinh. from Chilkat Inlet, Alaska. The name 

 Vitrea radiatula Alder is preferred for V. hammonis, and many 

 Alaskan localities are given. An addition to the American fauna is 



