THE LOACH 159 
False pearls are made by introducing this pearl mixture 
into very thin bulbs of glass, some of which are blown in 
irregular shapes, to increase the resemblance to real pearls. 
Liquid white wax or gum arabic in solution is afterwards 
injected into the beads to make them solid ; the glassy surface 
is then slightly dulled by exposure to the vapour of hydro- 
fluoric acid, and the illusion is so complete as to deceive all 
but expert scrutiny. 
Fourteenth Sub-Family: COBITIDINA: THE LOACH GROUP 
This group is formed of a number of genera of small 
fishes, none of them more than a few inches in length, 
distributed over the Old World and not represented in the 
New. Externally they suggest connection with almost 
anything rather than the last group described—the breams— 
resembling miniature barbels or gudgeon more than any other 
of the carps. The body is greatly elongated, the mouth is 
always surrounded by barbules, never less than six in number, 
and the air-bladder is partly or wholly enclosed in a bony 
capsule. Of the three European genera, two only are 
represented in Britain, each by a single species. 
The Loach (Nemachilus barbatulus) 
FINs. TEETH. 
Dorsal: g or to rays. Pharyngeal, in a single series. 
Anal: 6 or 7 rays. 
Ventral ; 7 rays. 
Pectoral : 12 rays. 
The genus Nemachilus—thread-tipped—consists of about 
fifty species, distributed in a wide range from the Malay 
Archipelago through Asia and Europe as far west as Ireland, 
but not represented in Denmark or Scandinavia. Of all 
these numerous species, only one, Nemachilus barbatulus, is 
