Supplement to "Nature," February 5, 1903. 



Vll 



sequence of, the encystment or quietude of the winter, 

 or they may result from an improved food supply de- 

 pendent upon similar seasonal maxima in the popula- 

 tion of Algae and Diatoms. The maxima, on the other 

 hand, may be only apparent, and exhibited relatively 

 only to a summer minimum which may bj supposed to 

 coincide with the maximal development of the natural 

 enemies of the Infusoria, such as the crustacean Cyclops 

 and the like. These difficulties of explanation may be 

 taken to represent only one set out of many problems in 

 natural history which the systematic study of these 

 lowly forms is likely to suggest. 



The appearance of Dr. Penard's companion mono- 

 graph upon the Rhizopod forms of the same locality is 

 very aptly timed. It contains the results of his laborious 

 researches into the very numerous and often ill-defined 

 species of this large group, with the fullest systematic 

 descriptions of their structure and habits, and it is 

 abundantly illustrated throughout with accurate drawings. 

 The author has not included among the Rhizopoda the 

 group Heliozoa, generally, but not very suitably, associated 

 with them. Dr. Penard has already published studies 

 of the Rhizopoda he has found elsewhere in Europe and 

 in North America, and it is significant, in connection 

 with what has been said above, that in his collections of 

 purely local forms in the Genevan district he finds 

 represented no less than 92 per cent, of the species 

 which have been described for the whole world, although 

 he has added a few hitherto undescribed species to the 

 list. In this estimate, he does not include, it should be 

 said, those forms of the Amceba class which are entirely 

 devoid of skeleton and less easily defined or identifi- 

 able. The volume contains a large bibliography, and 

 indices both to the subject-matter and to the species 

 described. 



In addition to the systematic description of the 

 Rhizopod fauna, Dr. Penard gives a series of separate 

 essays upon special points of interest in their general 

 morphology and behaviour — he deals with their growth, 

 the skeleton and its appendages, with the plasma, its 

 inclusions and pseudopodia, the nucleus, the contractile 

 vacuole, and finally with general questions of geo- 

 graphical distribution, reproduction and hybridity. The 

 most important variations of the shape and disposition 

 of the nucleus throughout the group are described and 

 figured, and these are strikingly numerous and diversified. 

 The author does not, however, give any systematic account 

 of the distribution within the Rhizopoda of the chief 

 Protozoan types of nuclear division. It has already been 

 shown by Schewiakoff and others that complexity in the 

 process of karyokinetic nuclear division is by no means 

 exhibited only by the more highly organised forms among 

 the Protozoa, and a good deal of light might be expected 

 to be thrown upon the relationships between cellular 

 elaboration and the karyokinetic figure by a systematic 

 examination of the nuclear behaviour throughout the 

 species of one group. Much no doubt remains to be 

 done, but Dr. Roux and Dr. Penard are to be congratu- 

 lated alike upon very notable achievements of skill and 

 industry. Their labours have borne fruit already, and 

 will long, wi believe, remain profitable 10 fellow-workers 

 in the same field. 



NO. I736, VOL. 67] 



A NEW ATLAS OF THE ATLANTIC OCEAN. 



Atlantische Ozean. Ein Atlas von 39 Karten, die 

 physikalischen Verhaltnisse und die Verkehts-strassen 

 darstellend. Zweite Auflage. Herausgegeben von 

 der Direktion. Deutsche Seewarte. (Hamburg: L. 

 Friederichsen und Co., 1902.) 



TOWARDS the end of the year 1898, the Deutsche 

 Seewarte published the second edition of its 

 well-known '■ Segelhandbuch " for the Atlantic Ocean, 

 but it was regretted at the time by the director, Prof. 

 Neumayer, that a new edition of the atlas was not forth- 

 coming. There were, however, very good grounds for 

 its non appearance, since it was considered that there 

 was not sufficient new material available to make it 

 worth while undertaking such a large piece of work. 



During the many years that have now elapsed since 

 the first edition of this atlas was published, a very 

 considerable amount of valuable information has been 

 accumulated, and advantage is now taken to bring the 

 atlas up to date and to make it complete and trustworthy 

 as regards every piece of information it conveys. 



Among some of the sources of the new data which 

 have been embodied in the work is that of the valuable 

 series of observations made by the Valdivia. Further, 

 advantage has been taken of another large piece of work 

 which has recently been brought to a conclusion, namely, 

 the ten-degree square investigation of the North Atlantic ; 

 these observations covered a zone extending from 20' 

 to 50° north latitude and stretching from the west ot 

 Europe to the east of North America, and they have 

 been published recently in no less than nineteen 

 volumes. 



Another store of valuable data was also ready at 

 hand, namely, that which had been collected by the 

 Deutsche Seewarte in connection with the Danish 

 Meteorological Institute and utilised for making its 

 synoptic weather charts. The work also of our own 

 Meteorological Office and Hydrographic Department 

 has also been usefully employed on many occasions, 

 and especially to fill up gaps not covered by German 

 observations. 



It will be seen that there was no lack of good material, 

 and Prof. Neumayer has so marshalled his facts that he 

 has been able to present seafaring men and meteor- 

 ologists with a trustworthy series of maps which illus- 

 trate our present knowledge of the mean physical and 

 hydrographical conditions of this important region of the 

 world. 



The thirty-nine maps that compose this atlas are 

 accompanied by clear explanatory remarks which de- 

 scribe their mode of construction and include the 

 sources of all the data that are contained in them. 



In a brief notice, it is not possible or even necessary to 

 describe each of the maps in this atlas, but it will suffice 

 to remark that they are arranged, not only to give the 

 mean meteorological, hydrographical, &c, condition for 

 the year, but the mean, in many cases, for important 

 individual months or groups of months. 



Thus, for instance, in the case of barometric pressure, 

 we have a chart showing the mean isobars of the 

 Atlantic Ocean for the whole year and lour m:ips for 



