Crustacean Life 



N9 



rater. The island, according to O'Neill, 1 may perhaps be considered a raised 

 lelta formation, and is mostly well covered with a luxurious vegetation, except 

 on the steep northern side and on the higher hills. Half a dozen ponds are 

 scattered over the island from the beach to its highest elevation; they are some- 

 times deep, and mostly situated in the swamps which form the upper part of 

 the creek-gullies, on the divide between the streams flowing north and south 

 on the island. 2 They are therefore generally much filled with vegetation (grasses, 

 Carex, Hippuris, etc.). I examined several of them in July-August, 1914 and 

 1916. The smaller ones had a teeming life of aquatic insects, water mites, 

 snails (Aplexa hypnorum), cladocera (Daphnia pulex and Eurycercus ylacialis), 

 copepods (Eurytemora, Diaptomus, Heterocope), turbellaria, etc.; while the 

 larger ponds contained the common phyllopods (Branchinecta paludosa), of 

 both sexes and unusually large (over 2 inches long), and certain of the largest 

 ponds a number of the arctic freshwater amphipods (Gammarus limnaeus). 

 It was interesting to note the extremely rich and varied invertebrate 3 life in 

 the various ponds upon this island; water birds visiting it from the mainland 

 during the summer have perhaps something to do with this. 



III. Vicinity of Bernard harbour, N.W.T. 



It is fortunate that we have for this area a detailed topographical map 

 (scale 2,000 feet to the inch) made by Messrs. Chipman and Cox of the southern 

 party of the Canadian Arctic Expedition during 1914-16. 4 The 

 map takes in the coast from the 2nd point (peninsula) northwest of our winter- 

 quarters, to the coast and small island opposite the east end of Chantry island, 

 including the latter. The map also shows the topography of the country inland 

 for some miles, immediately east and south of the station, including the eastern 

 parts of the two large lakes up the valley with the large creek (see below) . The 

 three largest lakes were sounded, also the sounds and bays between Chantry 

 island and the mainland coast, from the inner harbour at the station to the bay 

 in which the large "fishing creek" about four miles southeast of the station 

 comes out. 



The smaller pools and ponds, generally formed by the melting of the snow 

 in the spring, are illustrated in Plate IX, Part K, Vol. Ill; Plate III, Part A, 

 Vol. IV; Plate V, Part J, Vol. VII; and Plate IV, Part E, Vol. VIII of these 

 reports; a few more are reproduced here. (Plate II). 



When the warm weather comes in earnest (May-June) much melting water 

 is formed from the snow and accumulates in the many depressions on the snow- 

 free part of the tundra. Soon the overflow finds its way to the sea or helps to 

 increase the size of the various ponds and .lakes, as the ice of these melts from 

 the margin out. The small, shallow ponds become free of ice about the middle 

 of June, and in the first days of the next month the rivers and larger creeks have 

 broken up, and the deeper ponds are free of ice. 5 By the middle of July 

 the ice on the large lakes had been carried out to sea through their creek 

 outlets, or had been dissolved in the lakes. As the land was now 

 practically free of snow the heavy flow of water down the slopes had 

 stopped, which fact, coupled with the lack of further overflow of the various 

 ponds and lakes, makes these attain their maximum size at this time of the year, 

 and decrease from now on, under the influence of the warm weather in the latter 

 half of July and in August. The freezing of the ponds and lakes depends very 

 much upon what time in the fall the winter weather sets in permanently; some 

 times it takes place as early as the beginning or middle of September; in other 



1 Summary Report Geol. Surv. Canada, 1915, p. 236. 



2 See Plate I, fig. 2. 



3 Particularly Crustacea. 

 * Plate VI. 



6 Except for a layer in their bottoms. 



