The Rotatoria of the Canadian Arctic Expedition, 



1913-1918. 



By H. K. HARKING, 



Custodian of Rotatoria, U. S. National Museum. 



When the Canadian Arctic Expedition was organized with Mr. James 

 Murray as oceanographer and marine biologist, all students of the rotifers 

 looked forward to a considerable increase of our knowledge of the group and 

 hoped for a repetition of his success in the Antarctic as biologist of the Shackle- 

 ton Expedition. These expectations were frustrated through his death following 

 the loss of the Karluk and the career of an enthusiastic naturalist 'and tireless 

 worker was brought to an untimely end. No other member of the expedition 

 was able to make special collections of rotifers, but the general plankton collec- 

 tions made by the marine biologist of the southern party, Mr. Frits Johansen, 

 contained a considerable number of rotifers, which were assigned to the writer 

 for a report. Some collections made by Mr. J. M. Jessup while serving on 

 the Alaskan Boundary Survey have been included, as they belong to the same 

 faunal area and add somewhat to our scanty knowledge of the distribution 

 of the Rotatoria in the Arctic. Virtually all that we know on this subject 

 is to be found in Bergendal's Zur Rotatorienfauna Gronlands (1892), and the 

 value of this is somewhat minimized by his unfamiliarity with the group prior 

 to his visit to Greenland. 



While the species reported on here are not very numerous, 64 in all, they 

 furnish additional, even if superflous, evidence that climate is not directly a 

 factor in rotifer distribution. Four new species are described, among which a 

 pelagic Synchaeta is of special interest, as it is an addition to the extremely 

 small number of rotifers known to exist in the open ocean in water of normal 

 salinity. The total absence of the genus Brachionus, so abundant elsewhere, 

 is noteworthy; Bergendal mentions two species of this gemis from Greenland, 

 but his notes on these forms make it somewhat doubtful whether he really 

 found any Brachinoids. 



I am indebted to Mr. Frank J. Myers, of the American Museum of Natural 

 History, New York City, for drawing the plates accompanying this report. 



ORDER PLOIMA. 

 FAMILY NOTOMMATID^E. 



Notommata copeus Ehrenberg. 



A few specimens of this species were collected by Jessup in lakes on Old Crow 

 river flats, 55 miles north of New Rampart House, on July 10, 1911. 



Notommata cyrtdpus Gosse. 



Several specimens occurred in a collection from a pond near new Rampart 

 House, at the International Boundary and Porcupine river, made by Jessup 

 on June 12, 1911. 



Proales sordida Gosse. 



A few specimens in a collection made by Johansen among mosses and algae 

 from a pond at Chantry island, Bernard haitcur, Eclphin and Union strait, 

 on June 17, 1916. 



