48 GiJNTHEK. — FISHES OF GREENLAND. 



the voyage of the " Fox " in 72° (Bellot Strait), and in Spitz- 

 l^ergen they occur several degrees further north ; so that it is 

 probable that fishes of this family live in still higher latitudes. It 

 is of the highest interest to ascertain the extreme limits at which 

 fresh- water species can exist ; their existence being dependent on 

 the presence of food and on the conditions necessary for the de- 

 velopment of the spawn. Charr can live in Alpine pools which 

 are free from ice for a few weeks only in favourable seasons. 



a. . In collecting specimens of this family take large individuals 

 in preference to small ones, as young examples of less than 8 

 inches long, are but rarely suitable for specific determination. If 

 the specimens cannot be brought away, ascertain whether they 

 have or have not teeth along the body of the vomer, that is, 

 whether they are Charr or Trout. 



b. Has the locality in which they are found, a communication 

 with the sea ? and is there any reason to believe the fish to be 

 migratory ? 



c. If possible ascertain the depth of lakes inhabited by fish, and 

 whether the water is likely to freeze to the bottom. As some fish 

 of temperate regions (C^j^rmoiWis) can endure for a considerable 

 period complete enclosure in ice, it would be of interest to prove 

 experimentally that certain Arctic fish (marine or freshwater) 

 are endowed with a similar tenacity of life, and to see for what 

 period they can survive. 



d. Examine the stomachs of all Salmonoids, and note their 

 contents, some of which may be worth preserving. 



Instructions for making Observations on, and Col- 

 lecting the MoLLUSCA of, the A.RCTIC Regions. By 

 J. GwYN Jeffreys, F.RS. 



Exactly two centuries ago Frederic Martens, of Hamburg, first 

 noticed the MoUusca which he met with in his voyage to Spitz- 

 bergen and Greenland. These were the Clione papilionacea of 

 Pallas and Limacina arctica of Fabricius ; the former a naked or 

 shell-less mollusk, and the latter a smaller sh6ll-bearing species, 

 both being of the Pteropod order, which inhabit the surface of 

 the Arctic ocean in countless numbers, and are usually (but 

 questionably) supposed to constitute the food of whales. Since 

 that time Linne, Miiller, Fabricius, Chemnitz, Leach, Gray, 

 Broderip and Sowerby, Moller, Torell, Morch, Loven, Forbes, 

 Reeve, Albany Hancock, Davidson, and several others, have 

 described or noticed species from high northern latitudes ; besides 

 Sars and his Scandinavian fellow-workers, who have so carefully 

 and laboriously investigated the Mollusca of the Norwegian Coasts 

 within the Arctic circle. No nation has done, especially of late, 

 so much as Sweden to advance our knowledge of the Arctic Mol- 

 lusca. In 1857 and 1858, Professor Torell, aided and encouraged 



