264 VERTEBRATA: PISCES OR FISHES. 



streams of much that would otherwise tend to make the 

 waters impure. 



Fossil Ganoids are abundant, especially in the Devo- 

 nian rocks ; and these old ganoids were of enormous size, 

 and of the most wonderful structure, having vertebrated 

 tails and many other reptilian characteristics. 



SUB-SECTION VI. 

 THE ORDER OF LOPHOBRANCHII OR TUFT-GILLED FISHES. 



THE fishes of this group have their gills in small tufts 

 which are arranged in pairs along the branchial arches. 

 The name Lophobranchii is from two Greek words, lophos, 

 a tuft, and bragchia, gills. 



FIG. 310. 



FIG. 811. 



Pipe-fish, Sygnathus Peckianus, Storer. 



Sea-horse, Hippocampus hudsonius, Dekay. 



Some kinds of lophobranchs, as the Sea-horses, have the 

 tail prehensile, with which they often cling to marine 

 plants. 



The Pipe-fishes which, with the Sea-horses, belong to 

 the family of Sygnathidse are remarkable not only on 

 account of their form, but on account of their habits. 

 When the eggs are laid, the male receives them into a 

 sack, and carries them about until they are hatched ! In 



