CHAP, xx.]' FISHES. 457 



FAMILY 89. SYNGNATHID.E. (15 Genera, 112 Species.) 



" Marine Lophobranchii, with very small gill opening and one 

 soft dorsal fin." 



DISTRIBUTION. All the tropical and temperate seas. Some 

 species of Syngnathus, Doryichthys, and Cwlonotus enter fresh 

 water, and a few live in it exclusively. Siphonostoma, Syngna- 

 thus, Nerophis, and Hippocampus are British genera. The 

 Hippocampina (5 genera, 25 sp.), or Sea-horses, are peculiar to 

 the Indian and Pacific Oceans, except three or four species of 

 Hippocampus in the Atlantic and Mediterranean. 



Order VI. PLECTOGNATHI. 



"Fishes covered with rough scales or shields, having a 

 narrow mouth, and soft posterior dorsal fin." 



FAMILY 90. SCLEKODEBMI. (7 Genera, 95 Species.) 

 " Marine Plectognathi, with toothed jaws." 



DISTRIBUTION. Temperate and Tropical seas, but much more 

 abundant in the Tropics. 



FAMILY 91. GYMNODONTES. (10 Genera, 82 Species.) 



" Marine or fresh- water Plectognathi, with jaws modified into 

 a beak." 



DISTRIBUTION. Temperate and tropical regions. 



Some species of Tetrodon are found in the rivers of Tropical 

 America, Africa, and Asia, Species of Tetrodon and Ortha- 

 goriscus have been found on the British coasts. 



