Crustacean Life N 17 



besides the common amphipods {Gammarus limnaeus), the two interesting 

 marine "relicts" Mesidothea entomon, (end of June, 1915), and Mysis relicta 

 (October 1915), proving that these crustaceans are also to be found in 

 certain of the inland lakes. In the case of Mysis relicta its occurrence in these 

 lakes is probably a case (see p. 3, Part B, in this volume) of a true "relict," 

 from the time the lake in question was a part of the sea; in the case of Mesidothea 

 entomon however I have personally observed (see p. 21-22, Part D, in this volume), 

 that it ascends certain suitable creeks to reach a lake, though in other lakes it 

 may be a true "relict" form. It is therefore quite possible that several others 

 of the large lakes inland at Bernard harbour have a similar origi'n and under 

 investigation will show the same character (deeper parts saline, marine elements 

 in its fauna, etc.), as the one described on p. 14-16n. 



About the lakes at Bernard harbour which have a size between the large ones 

 described above, and the true ponds, little need to be said beyond what is given 

 in my description of the insect life.^ Most of them are merely enlarged ponds 

 in their nature, and few exceed one fathom in depth. On the detail map of the 

 harbour several of such lakes will be noticed inland, south of our winter quarters. 



Perhaps the best criterion for what may be considered a lake and what a 

 pond in this vicinity, there being all grades between them, is the presence or 

 absence of the typical and common freshwater amphipod {Gammarus limnaeus) , 

 which is not found in ponds, but only in lakes and their tributaries. Here they 

 feed upon the still smaller animals occurring pelagically (copepods and cladocera) 

 or in the vegetation, and upon the latter itself. Their occurrence is thus an 

 interesting contrast to the other large freshwater crustaceans (Euphyllopoda), 

 which principally occur in ponds, lagoons or smaller lakes along the arctic 

 coast. Thus I did not observe any fairy shrimps in the large lake described on p. 

 12n, but there were a great number of them in a large pond situated in the swamp 

 surrounding this lake (July, 1915). Nor was Lepidurus arcticus observed in, or 

 collected from any of the three large lakes investigated at Bernard harbour. 

 The cold water form of fairy shrimps {Artemiopsis stefanssoni) may of course 

 occur in other elevated ponds in this vicinity than the three given on p. 11n. 



References. 

 Besides the information about certain lagoons, lakes and ponds given in this^ 

 report, descriptions of other bodies of freshwater along the arctic coast of America 

 west of longitude 110° West, with occasional references to their crustacean life, 

 are to be found in the following accounts of earlier expeditions and reports in 

 this series: 



(1) Coast beetween Bering strait and latitude 71° North: See "Narrative 

 of a voyage to the Pacific and Bering strait 1825-28," by Capt. F. W. Beechey, 

 London, 1831, Part I, pp. 247-333; also Schrader and Peters, "A Reconnaissance 

 in Northern Alaska across the Rocky Mountains, along Koyukuk, John, 

 Anaktuvuk and Colville Rivers, and the Arctic coast to Cape Lisburne in 1901." 

 Professional Paper 20, U.S. Geological Survey, Washington, 1904, pp. -49-50. 



(2) Vicinity of Point Barrow: See "Report of the International Expedition 

 to Point Barrow, Alaska, 1881-83," Washington, 1885, pp. 149-51. 



(3) Coast between Point Barrow and International Boundary: See "The Can- 

 ning River Region, Northern Alaska," by Ernest de K. Lefl&ngwell, Professional 

 Paper 109, U.S. Geological Survey, Washington, 1919; for rivers, ground-ice, etc. 



(4) East side of Mackenzie river delta: See "Arctic Searching Expedition," 

 1848-49, by Sir John Richardson, London, 1852, pp. 152-54. 



(5) Cape Bathurst and Young point, Northwest Territories: See Volume 

 III, Part K, pp. 17-18, of this series. 



(6) Stapylton bay to Coronation gulf and Wollaston land (Victoria island) : 

 See Volume XII, pp. 14-26, of this series. 



"See Part K. Vol. Ill, of these reports. 



Note — The six photographs reproduced in the report were all taken by the author. 



43788—2 



