405 



NOTICES OF NEW BOOKS, 



The Foraminifera of the Atlantic Ocean. Part I. Astrorhizidae.— 

 By J. Cushman. Smithsonian Institution, United States National 

 Museum, Bulletin 104, i-vii and 1-111, pis. 1-39. Washington : 

 Government Printing Office. 1918. 



J. A. Cushman, having completed his useful series of monographs on 

 the Foraminifera of the Pacific, is now devoting his attention to those 

 of the Atlantic, The amount of material at his disposal resulting from 

 the records of numerous zoologists working on the European coastline, 

 supplemented by the extensive dredgings and soundings of the U.S. 

 Bureau of Fisheries, is naturally much larger than was available for the 

 comparatively unexplored Pacific, 



The Astrorhizidge are mainly benthic organisms, and many species 

 have consequently a world-wide distribution, because physical conditions 

 in the deep sea are subject to very little variation anywhere. Darkness 

 and a temperature just above freezing point are the chief physical 

 features. Bound the poles, and within the influence of the cold currents 

 which originate in the polar seas, the Astrorhizidte extend into com- 

 paratively shallow water. Hence the abundant Astrorhizid fauna which 

 has been dredged in recent years in the deeper areas of the com- 

 paratively shallow North Sea, and in the area to the north of the 

 Wyville Thomson Ridge between Scotland and the Faroe Islands. In 

 the warm area to the south and west of the Ridge the same species are 

 found at greater depths. 



These conditions are probably duplicated on the eastern coast of the 

 United States, where the Labrador Current and the Gulf Stream meet. 

 Cushman in his introduction refers to the dissimilarity of the benthic 

 fauna to the nortli and south of Cape Hatteras, but does not appear to 

 have appreciated the enormous influence which the Wyville Thomson 

 Ridge exercises on the fauna of north-western European seas. It would 

 be interesting to compare lists ♦of Foraminifera from similar depths in 

 these four widely-separated areas, and as the material from the European 

 side is already available we hope that Cushman will publish such a com- 

 parative table in his forthcoming reports. 



Physical conditions on the two sides of the Atlantic being so similar, 



