CHAPTER VII. 



FRESH-WATER FISHES OP THE ORDER PHYSOSTOMI (continued]. 



FAMILY CLUPEID^E GENUS CLUPEA : Shad Twaite Shad Whitebait- Black S.-:. 

 Herring Caspian Herring. 



FAMILY: CLUPEID.E. 



GrENUS: ClUpGa (CuVIER). 



THE allies of the Herring- comprise about eleven genera, which are found in 

 all seas, sometimes with species entering rivers. This, however, is never the 

 case with the Anchovies, though some of their Eastern allies, like the genus 

 Coilia, are found in the Ganges and Irawaddy. Another genus, Chatoersus, 

 enters rivers on the coasts of North and Central America, Australia, and the 

 East Indies, and has become naturalised in some lakes. 



The only genus with fresh-water representatives in Europe is the numerous 

 and widely distributed genus Clupea. The fishes of this type have the head 

 naked. The body is covered with scales ; it is compressed, and the abdomen 

 forms a serrated edge, which extends forward into the region of the throat. 

 The margin of the upper jaw is formed in front by the pre-maxillary bone, 

 and at the side by the maxillary bone, which consists of three elements. The 

 upper jaw does not project beyond the lower. The cleft of the mouth is 

 of moderate width ; the teeth are rudimentary, but their variable condi- 

 tion aids in distinguishing the multitudinous species into groups. Thus the 

 typical genus Clupea, which comprises only the Common Herring, the Calif or- 

 nian Herring, and Herrings of the Black and Caspian Seas, has a conspicuous 

 oval patch of minute teeth on the vomer ; while a large number of species 

 from the Atlantic, Indian Ocean and Archipelago, China, and Australia, have 

 minute teeth on the palate, and none on the vomer. The European fresh- 

 water representatives belong to a third group, in which there are no teeth 

 at all, though some of their allies have teeth on the tongue. These fishes 

 have the dorsal fin opposite to the ventral. The caudal is forked; the anal fin 

 has fewer than thirty rays. The stomach has a blind sac, with many pyloric 

 appendages. 



