250 



SCIENCE 



[N. S. Vol. XXXIII. No. 842 



secondly, the angle that the ray was de- 

 signed to have with the commonly perpendicu- 

 lar plane, when the above formula will 

 prove itself, by giving us the correct bend 8 in 

 the ray that the instrument was designed to 

 produce. Whereupon any error on deflection 

 in the entering ray either does or does not 

 make a new angle 6' with the commonly per- 

 pendicular plane, giving us, therefore, by the 

 above formula the new value of 8. 



Alan S. Hawkesworth 

 University of Pittsbubgh 



the insufficiency of data on environment 

 given in papers describing deep-sea and 



other marine organisms 

 To THE Editor of Science : In examining a 

 number of recently published papers on corals, 

 foraminifera and other marine animals, espe- 

 cially for the purpose of ascertaining the tem- 

 perature conditions under which the organ- 

 isms live, I have been particularly impressed 

 by the fact that very rarely are any definite 

 data given on the temperature of the waters 

 from which they were taken. As it is a gen- 

 erally known biological fact that temperature 

 is one of the most influential factors in deter- 

 mining geographic distribution, it is highly 

 important that precise information on this 

 subject should be available. In fact, the data 

 on the physical conditions under which an 

 organism was collected should always be pre- 

 sented as fully as possible. Depth, tempera- 

 ture, nature of the bottom, and relations to 

 marine currents, are important factors. As 

 so many zoologists are engaged on the descrip- 

 tion of marine faunas, and as it is more or 

 less habitual to give very meager data on the 

 conditions under which the organisms de- 

 scribed live, this appeal for more detailed in- 

 formation is made to the body of investigators 

 through the columns of Science. 



T. Wayland Vaughan 



SCIENTIFIC BOOKS 

 The Age of Mammals in Europe, Asia and 

 North America. By Henry Fairfield Os- 

 BORN. Illustrated. New York, The Mac- 

 millan Co. 1910. 



Students of paleontology have awaited im- 

 patiently the past few years a promised work 

 on extinct mammals by Professor Osborn. In 

 his " Age of Mammals," as it has recently 

 appeared, expectations have been more than 

 realized. For more than a century, beginning 

 with the classic researches of Cuvier, our 

 knowledge of extinct vertebrates has been in- 

 creasingly widened, and of no group so greatly 

 as of the mammals. In North and South 

 America, throughout Europe, in India, and 

 more recently in Africa, discoveries have fol- 

 lowed discoveries so rapidly that all but the 

 expert have nearly given up in despair the 

 attempt to follow and understand. And it is 

 superfluous to say that in no part of the world 

 has the progress of our knowledge been so 

 rapid as in North America. Those famous 

 pioneers in American paleontology, Leidy, 

 Cope and Marsh, followed soon by Scott and 

 Osborn, and later by Wortman, Hatcher, 

 Matthew, Merriam, Sinclair, Gidley, Peter- 

 son, Douglass, Loomis, as well as others whose 

 names may be omitted here without invidious- 

 ness, have contributed abundantly and meri- 

 toriously to our knowledge of the history of 

 mammalian life in North America. 



But, for some years it has been growing 

 more and more evident that it was time that 

 an inventory should be made of what we know. 

 And this has now been done ably by Professor 

 Osborn in this voluminous work of more than 

 six hundred pages. That there is no place in 

 the world where such a work could be written 

 as the American Museum of New York City, 

 with its extensive collections, and various 

 experts in paleontology, especially Dr. Mat- 

 thew, for aid and advice, vertebrate paleon- 

 tologists know full well. That there is no 

 one who could treat the subject more broadly 

 and comprehensively than Professor Osborn 

 will, also, be as readily admitted. Indeed 

 there are few who are competent to criticize 

 expertly the work as a whole, as the reviewer 

 is painfully conscious, since he knows that he 

 is not one of them. Vertebrate paleontology 

 has advanced with such enormous strides 

 within the scientific career of the present 

 writer even, that it is no longer possible for 



