OF THE BRITISH ISLANDS. 87 



species of Corregoui are likewise gregarious Salmonidae, 

 restricted, however, like the Chars, with one exception (No. 

 1 50, which is both a marine and freshwater form), to our 

 larger upland lakes, and subject in a similar manner to 

 much local variation. In their size, shape, and their silvery- 

 colouration they bear no inconsiderable resemblance to 

 the members of the Herring tribe, whence their popular name 

 of " Freshwater Herrings," but may be immediately 

 distinguished from such fish by the possession of a distinct 

 adipose dorsal fin. The four British species as recognised 

 by most authorities are the Houting, or sharp-snouted 

 Corregonus {Corregonus oxyrhynchus), No. 150 ; the Guiniad 

 of Bala, and other North Wales lakes {C. clupeoides)* No. 

 151 ; the Vendace of Scotland (C. vendesius), No. 152 ; and 

 the Pollan and Powan of Ireland and Northumberland (C. 

 pollan), No. 153. The Grayling {Thymallns vulgaris), No. 

 154, is an example of the Salmon family, specially abun- 

 dant in the streams of Hampshire and other of our 

 southern counties. The Hebridal Smelt {Argentina 

 spliyrcena), No. 155, which closes the list of the British 

 Salmonidae, is a small northern marine type, not unfre- 

 quently taken among the islands to the North of Scotland, 

 and of which a preserved specimen will be found in the 

 series forming the Day Collection. 



FAMILY III.— Pikes {Esocidm). 



Body covered with scales ; barbels none. Margin of upper 

 jaw formed mesially by the intermaxillary and laterally by 

 the maxillary bones ; no adipose fin, the single dorsal fin 

 developed towards the caudal extremity of the body. 



* Specimens of this type from Bala Lake, the gift of Sir Watkin 

 Williams Wynn, Bart., are on view in the Buckland Museum. 



