970 



SCIENCE 



[N. S. Vol. XXX. No. 783 



extending Arctic pack ice in the hope of find- 

 ing a passage toward the eastern shore of 

 Greenland through some break in this im- 

 passable harrier. Nearly seven degrees of 

 southing were traversed before the Belgica 

 could be headed to the westward and, amongst 

 the broken floe ice between the pack ice and 

 the Greenland coast, again struggle to the 

 northward. Under these circumstances a lati- 

 tude of about 18° 16' was attained, when the 

 ship retraced her course, leaving the broken 

 ice at a point nearly west of Jan Mayen and 

 thence proceeding to the westward of Iceland, 

 touching at Reykjavik, and so homeward. 



Among the special objects of the cruise 

 was the extension and confirmation of Nan- 

 sen's observations and theories in regard to 

 the conformation of the sea bottom, the cur- 

 rents off the east coast of Greenland, the dis- 

 tribution of marine animal life in the plank- 

 ton and on the surface of the sea, and the 

 inter-relations of Arctic and North Atlantic 

 waters mingling in the Greenland Sea. 



The scientific results are detailed in this 

 truly magnificent volume, in which, of the 

 printer's and cartographer's art, nothing has 

 been spared in the endeavor to approach per- 

 fection. 



Geographically the more interesting results 

 were the latitude attained by the vessel, a 

 considerable distance further than previous 

 navigators on this dangerous coast; the dis- 

 covery of a number of new islands off the 

 coast of Greenland; and of a submarine 

 moraine, about forty miles broad-off the 

 Greenland coast and parallel with it, which 

 received the name of Belgica Bank. 



Space would not sufiice to analyze in detail 

 the work accomplished, but a summary of the 

 contents will enable those interested to form 

 a general idea of the results. 



A summary, with synoptical charts of the 

 meteorological conditions during the cruise, 

 is given by Dan La Cour. O. B. Boggild con- 

 tributes a memoir on the submarine sediments 

 and their distribution, with notes on the sub- 

 marine moraine before referred to and the 

 continental rocks collected. Ostenfeld, C. 

 Jensen, Ferdinandsen, Winge and Deichmann 



Branth discuss the phanerogams, mosses, fungi 

 and lichens obtained. Helland-Hansen and 

 Koefoed discuss the hydrography in a division 

 of 220 pages luxuriously illustrated by maps 

 and sections, and more than 100 pages are 

 given to a study of the plankton by Koefoed 

 and others. C. Hartlaub contributes a me- 

 moir on the medusas, and Koefoed one on the 

 fishes with fine illustrations of numerous 

 larval forms. J. Grieg describes the inverte- 

 brates collected, first on the coast of Spits- 

 bergen and, secondly, from the Greenland Sea, 

 with the assistance of several other naturalists 

 who have determined the species of special 

 groups. Some observations follow on the 

 food of the walrus, bearded seal, T ring a stri- 

 ata, and the tom cod. The volume closes with 

 tables of the dredging stations, an enumera- 

 tion of the scientific staff of the expedition, 

 and a full table of contents; but curiously 

 enough, no index. 



This splendid volume, with its wealth of 

 carefully conducted observations, will form a 

 permanent monument to the liberality and 

 good sense of the noble patron of the expedi- 

 tion and a happy contrast to the barren ex- 

 ploits of unscientific pole seekers with which 

 from time to time the daily press concerns 

 itself. Wm. H. Dall 



SPECIAL ARTICLES 



PRE;:yIMINARY NOTE ON THE CHROMOSOMES IN THE 



OOGENESIS, FERTILIZATION AND CLEAVAGE 



OF CERTAIN HEMIPTERA 



In the recent work on the spermatogenesis 

 of the Hemiptera heteroptera it has been 

 shown that in the members of some families 

 of this group, notably the Coreidse, the sperma- 

 togonia have an odd number of chromosomes, 

 one of the latter being the unpaired idiochro- 

 mosome or " accessory " chromosome. Owing 

 to the fact that this chromosome passes un- 

 divided to one pole of the spindle in one of 

 the maturation mitoses while the others divide 

 equally in both, two classes of spermatozoa are 

 formed in equal numbers, one class having the 

 idiochromosome, the other lacking it. The 

 oogonia have been shown to have an even 

 number of chromosomes, there being two equal 



