310 NATURAL SCIENCE. April, 



about things. The commercial maps are not so satisfactory ; it is 

 difficult to follow the highways of commerce by land and by sea upon 

 them. The editors say that, in the construction of the maps showing 

 the distribution of plants and animals, " particular attention has 

 been paid to such products as are useful to man and enter largely 

 into commerce." We have already referred to the absurd inade- 

 quacy of these, but in the introduction, as distinguished from the 

 preface, the contradictory statement is made that "our maps show 

 the supposed native countries of these plants " (i.^., characteristic 

 plants and those of economic importance), " and not the countries in 

 which they are being cultivated at the present time." Messrs. Scott 

 Keltic, Mackinder, and Ravenstein have associated their names with 

 what is in many places a mere burlesque of the great science of 

 geography. 



Dredging and Distribution in Danish Seas. 



DET VIDENSKABELIGE UdBYTTE AF KaNONBAADEN " HaUCHS " TVOGTER I DE 



DANSKE Have indenfor Skagen i Aarene, 1883-86 (Chef : Premierlieutenant 

 C. F. Drechsel). Udgivet paa Bekostning af Ministeriet for Kirke- og Under- 

 visningsvsesenet ved C. G. Johan Petersen. Pp. 464, 6 pis. and 2 maps, 4to; 

 atlas of 43 maps, fol. Kjobenhaven, 1889-93. 



This work, which has just been published under the auspices of the 

 Danish Government, is one of no common interest for those who 

 believe that a careful investigation of the conditions affecting the dis- 

 tribution of common animals within a limited area is likely to be of 

 as much utility in the solution of important biological problems as is 

 the collection of new species from far-off lands. 



In the year 1883, Captain Drechsel applied to the authorities of 

 the Zoological Museum in Copenhagen to recommend him a natu- 

 ralist who would spend a few weeks on board his ship making 

 collections for the Museum and investigating the animal life of the 

 Danish seas in general. The choice fell upon Dr. Petersen, and has 

 been amply justified by the results of his work published in the 

 volume now under notice. 



During the first season Captain Drechsel and Dr. Petersen 

 elaborated a plan of campaign, which was "not merely to seek for 

 species new to the fauna of the district, but first and foremost to 

 acquire a knowledge of the distribution of the commonest animals, 

 and at the same time to investigate as far as possible those natural 

 conditions, such as temperature, composition of the bottom, etc., 

 which might be supposed to exercise an influence upon the distribu- 

 tion and life of the animals. This plan was carried out in the course 

 of the three following summers, 1884-86, and, with this object in 

 view, dredgings were made at as many stations as possible in the 

 Kattegat, so that on the basis of these observations conclusions might 

 be drawn regarding the distribution in those waters of at all events 

 the commonest animals, especially the invertebrata." Wherever 

 possible both dredge and trawl were used, and the process was carried 

 on till it became possible to predict with a fair amount of certainty 

 what species would be obtained from any particular haul. 



More than 500 stations were occupied, and in almost every case, 

 in addition to the exact geographical position, there are given the 

 depth, the nature of the bottom, the temperature of the water and its 

 specific gravity both at the surface and the bottom. The material 

 obtained was placed in the hands of different specialists for examina- 

 tion, and their reports are incorporated in the present volume. The 



