20 O 13 8 E R V A T IONS 



mean temperature of the atmosphere; as in the 

 Vipacco, near Coritzea, and in the streams which 

 gush forth from the limestone caverns of the Noric 

 Alps. 



" Besides temperature, Grayling require a pecu- 

 liar character in the disposition of the water of 

 rivers. They do not dwell like Trout in rapid 

 shallow torrents ; nor like Char or Chub in deep 

 pools or lakes. They require a combination of 

 stream and pool ; they like a deep and still pool 

 for rest, and a rapid stream above, and gradually 

 declining shallow below, and a bottom where 

 marl and loam is mixed with gravel ; and they are 

 not found abundant except in rivers that have 

 these characters." 



The Rev. Mr. Low says, (p. .), " The Gray- 

 ling is frequent in the Orkney Islands, as it is in 

 Lapland and Switzerland ; but it is rare in Scot- 

 land, and confined in England to the Avon near 

 Salisbury, the Ure near Fountain's Abbey, the 

 Dee between Corwan and Bala, and the Dove ; 

 also the Trent, the Wharfe, the Humber, the Rye, 

 and the Derwent." 



The Grayling is seldom known to take the 

 Minnow, and I have never found any in his 

 stomach, although I have taken out much Larvae 

 covered with cases of sand, and some having six 

 stones attached to each, as also Larvae when in the 



