THE CRUSTACEA EUPHAUSIACEA OF THE UNITED STATES 



NATIONAL MUSEUM. 1 



By H. J. Hansen, 



Of Copenhagen, Denmark. 



In 1911 I published a paper entitled: The Genera and Species of 

 the order Euphausiacea, with Account of Remarkable Variation. 2 

 Every valid species hitherto established was enumerated, and pre- 

 liminary descriptions were given of a number of new forms and 

 of some little known species. At that time the order comprised 

 73 species. The previous year my treatise on the Euphausiacea 

 gathered by the Siboga expedition had been published, and I had 

 also at my service vast material from many sources, especially 

 the collection in the Copenhagen Museum, together with the large 

 collections procured, respectively, by the Prince of Monaco in the 

 North Atlantic, by the Swedish Antarctic Expedition, by Dr. Alex- 

 ander Agassiz during his cruise on the Albatross in the tropical east 

 Pacific Ocean in 1904-1905, etc.; but the fauna of the north Pacific 

 with Bering Sea was nearly unknown, and the material collected by 

 the Albatross, the Grampus, etc., in the Atlantic off the United States 

 had never been worked out. In order to fill such gaps in our knowl- 

 edge of the world's fauna I applied to the authorities of the United 

 States National Museum, who most kindly lent me for investigation 

 its entire material. It contains several interesting Pacific forms, 

 among which are a new genus, two new species unknown to me from 

 any other collection, good material of two rare and hitherto imper- 

 fectly known species, etc. In the preliminary paper mentioned I 

 established the new genus and species and added observations on some 

 other forms. But the rich collection, which at present fills about 

 600 vials and bottles and comprises 46 species, deserves to be dealt 

 with in a separate paper, containing descriptions with figures of sev- 



1 Since the author completed this paper and transmitted it to the United States National Museum 

 there have been published three papers dealing with the Euphausiacea which add considerably to our 

 knowledge of their distribution. They are as follows: W. M. Tattersall, The Schizopoda, Stomato- 

 poda and nonantarctic Isopoda of the Scottish National Antarctic Expedition (Trans. Roy. Soc. Ed- 

 inburgh, vol. 49, pt. 4, 1913. Carl Zimmer, Die Schizopoden der Deutschen Siidpolar Expedition, 

 1901-1903, (Deutsche Siidpolar Expedition, 1901-1903, vol. 15, Zoologie, 7, 1914). Calvin O. Esterly, 

 The Schizopoda of tho San Diego region (Univ. of California Publ., vol. 13, No. 1, April 14, 1914). The 

 present author regrets that he has not been able to take these papers into consideration in his treatment 

 of the topic "Distribution" under the various species here discussed. 



a Bull. l'Inst. Oc<San. Monaco, No. 210. 



Proceedings U. S. National Museum. Vol. 48— No. 2065. 



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