126 



LOWER VERTEBRATES. 



rounded by rather long barbels. The body is usually covered with small scales, the 

 pharyngeal teeth are few in number, and the air-bladder is enclosed in a bony capsule. 

 Many of the species are provided with an erectile spine below the eye. 



The loaches are bottom fishes, feeding on insects aiid worms, and often burying 

 themselves in the mud or sand. They often lie quiescent for a considerable time, 

 moving very quickly for a little distance when disturbed, in a manner not unlike that 

 of the darters and gobies, which occupy a similar position in American waters. 



Some species of loach are found in most European streams, but none occur either 

 in America or Africa. The commonest European species is Nemachilus barbatula. 



The largest family of fishes is that of Cypeiuidje, the carp family. It comprises 



Fig. 83. — a, Misgurnus fossUis ; b, Cobitis tmnia ,■ c, NamcLchilus barbatula, loaches. 



upwards of one hundred and seventy-five genera and nearly two thousand species, found 

 in the rivers of all parts of the world except South America, Australia, and the Polar 

 regions. To this family belong the various fishes which have received the vernacular 

 names of carp, chub, dace, roach, minnow, bream, and shiner. Among the Eventog- 

 nathi, they are distinguished by the following characters : The premaxillaries always 

 form the entire margin of the upper jaw : the mouth is ah\'ays toothless ; the lower 

 pharyngeal bones are falciform, nearly parallel with the gill arches, and each provided 

 with a small number of comparatively large teeth. These teeth are arranged in one, 

 two or three rows, the main row containing from four to seven teeth, the other rows, 

 if present, from one to three. The teeth of the main row are in some cases coarse 

 arid blunt, forming molars. In other cases, they are slender and straight, with a 

 narrow groove (grinding surface) on the inner cutting edge towards the point. In 



