150 SOME NEW BOOKS [august 1899 



Bilder, by Holzel of Vienna, the forestry maps of Sargent, showing the distri- 

 bution of trees in North America, and many other items of importance which 

 suggest, like the journal itself, the great progress at present being made in the 

 science and teaching of geography. 



In Science of June 23 Prof. R. W. Wood describes his diffraction process 

 of colour-photography, which is really a variation of the three-colour method ; 

 and Prof. E. Thorndike discusses the mental fatigue of school work, furnishing 

 additional data which render more probable his previous conclusion that 

 " the mental work of the school clay does not " [at the time] " produce any de- 

 crease in the ability to do mental work." 



The eye of the Amphipod Crustacean Biblis serrata receives attention at 

 the hands of Dr. S. D. Judd in the May issue of the Proc. Biol. Soc. Wash- 

 ington, and is found to be remarkably different from the corresponding organ 

 of Gammarus. It appears to be a compound eye constructed on the general 

 plan of an ocellus, but furnished with a space which may be the functional 

 representative of the space occupied by the vitreous humour in the vertebrate 

 eye. Further investigations are, however, needed before the full significance 

 of all parts of this organ can be determined. 



The Alaskan Moose, or Elk, has long been known to be the largest representa- 

 tive of its kind, and it appears to be mainly on this feature that Mr. G. S. 

 Miller relies in describing it as a new species (A/ces gigas) in the recent issue 

 of the serial last quoted. Most English writers regard all the living repre- 

 sentatives of the Elk as referable to a single wide-spread species. In recognis- 

 ing three specific forms in what is essentially one and the same animal, Mr. 

 Miller shows the value to be attached to species recently named by American 

 writers among the smaller Mammals. 



'& 



Prof. Weismann's essay on regeneration appeared contemporaneously in 

 Natural Science (in English) and in the Anatomischer Anzeiger (in German). 

 A reprint of the German edition has been published in pamphlet form by Mr. 

 Fischer of Jena, to whom we are indebted for a copy. It is entitled " Thatsachen 

 unci Auslegungen in Bezug auf Regeneration," occupies 31 pages, and costs 60 

 pfennigs. 



