SALMON 



85 



extremely numerous in species in the Old and New Worlds, of 

 which the following are well known in England : — The Roach 

 [L, rutilus), the Chub [L. cephalus)^ the Dace {L. leuciscus), the 



Fig. 72. 





Mahaseer {Sarhus mosal), 



Rudd (L. erythrophthalmus), and the Minnow {L. phoxinus). 

 Other British Cyprinoids are the Tench [Tinea tinea), the Bleak 

 [Alhumus alburnus), the Breams [Abramis brama and blieea), and 

 the Loaches {Nemaehilus barbatulus and Cobitis tcenia) . 



The HaplochitonidcB are a small but interesting family, inasmuch 

 as they represent the Salmonolds in the temperate parts of the 

 Southern Hemisphere. They differ from the latter family in the 

 structure of the jaws,and by the total absence of pyloric appendages; 

 but they possess an adipose fin like the Salmonoids. Two genera 

 are known : one, Haplochiton, is abundant in the lakes and streams 

 of the Falkland Islands, Patagonia, and Chili ; these fishes have 

 the general appearance of a Trout, but are naked. The second 

 genus, Prototroctes, is scaly, and resembles a Vendace [Coregonus) ; 

 the settlers of South Australia and New Zealand call them Grayling. 



The Salmonidee (Case 21) are one of the- most valuable families [Case 21.] 

 of the Class of Fishes. They are inhabitants of the sea and fresh 

 water; but the majority of the marine genera are deep-sea forms. 

 The freshwater forms are peculiar to the Temperate and Arctic 

 zones of the Northern Hemisphere, one only (a Smelt) occurring 

 in New Zealand. Many migrate periodically or occasionally from 

 fresh water to the sea, or vice versa. The genus Halrno, containing 

 the Salmon, Trout, and Char, is abundant in species, some being 



