HERRINGS. 91 



three feet in length, with a long, strongly compressed body and a 

 saw-like edge on the belly. The dorsal fin is short-based and 

 opposite to the anal, which is long. One of the most interesting 

 features of Chirocentrus is the presence of a spiral valve in the 

 intestine ; such a valve is present in all Ganoid fishes, and the 

 occurrence of the valve, even in a reduced form, in this Teleostean 

 fish is of interest as pointing to the relationship between the lower 

 Teleostean fishes and the Ganoids. Poriheus, Ichthyodectes and 

 Saurodon are Cretaceous fishes allied to Chirocentrus, but of much 

 greater size and with the teeth lodged in sockets ; by some 

 authorities these fishes are placed in a separate family, the Sauro- 

 dontidse. 



Included within the genus Clupea are the Herring, Pilchard, 

 Sprat and Shad, fishes of northern distribution, with deciduous 

 scales, a row of ridge-scales extending along the lower edge of the 

 body from the shoulder girdle to the anal fin, a forked tail, a feeble 

 dentition, and no lateral line. Most of the species are food fishes, 

 but some of the tropical species are poisonous. The Herring, Herring. 

 Clupea harengus, 255, is found on both European and American 

 sides of the North Atlantic, and is especially abundant in the 

 North Sea and off Norway. It may thus be regarded as a 

 northern and a cold water fish. The " Herring" of the North 

 Pacific is of another species, Clupea pallasi. The Herring fisheries of 

 the North Sea take place during the spawning season, which reaches 

 its height in June off Shetland, and in November off" Lowestoft. 

 The fishing fleets move southwards as the centre of shoaling shifts 

 from point to point. The spawn of the Herring, unlike that of 

 most other food fishes, even the allied Pilchard and Sprat, sinks 

 to the bottom ; but the fish are mostly caught near the surface in 

 drift-nets, which may be more than a mile in length for each boat. 

 About 8,000,000 cwts. of Herrings, valued at more than 

 £.2,000,000, are annually landed in Great Britain. The largest 

 Herrings come from Loch Fyne, in Scotland. 



The little fishes that go by the name of Whitebait consist of White- 

 the fry of Herrings and Sprats, both of which have a predilection b^*- 

 for brackish water. The Thames Whitebait consists chiefly of 



