144 BRITISH FRESH-WATER FISHES 
The Tench (Zinca vulgaris) 
Fins. TEETH. 
Dorsal ; to to 12 rays. Pharyngeal, wedge-shaped, slightly 
Anal: g or 10 rays. hooked at the ends, in a single 
Ventral; io or 11 rays. series, five on the left side of the 
Pectoral: 15 to 17 rays. throat, four or five on the other. 
In the sub-family or group Leuciscina, whereof so many 
genera and species bear such a close external resemblance 
to each other, the tench stands out distinct, to be confused 
with no other fish. It is a genus of but a single species, 
Tinca vulgaris, whereof the most obvious characteristic are 
the exceedingly small scales, numbering more than one 
hundred along the lateral line, deeply embedded in the dark 
olive epithelium of the skin, through which they glisten 
like myriads of golden dots. The secretion of mucus is 
exceedingly abundant, rendering the fish as slippery as any 
eel. The tench is also distinguished from the rest of this 
group by a short barbule at each angle of the mouth. A 
variety known as the golden tench, said to have originated 
in Germany, and to have been introduced into Britain 
during the last century, is described as an_ exceedingly 
handsome fish. The skin is of a rich orange colour, 
irregularly blotched with the normal colour of the species. 
This change of colour must be attributed to incipient 
albinism, such as gives distinction to the gold-fish (Cyprinus 
auratus). In 1878 Mr. Higford Burr had a great number 
of them, the offspring of a single pair, which had bred freely 
in one of his ponds at Aldermaston Park, near Reading. 
The ordinary colouring of the tench is a rich olive green 
or brown, shaded into light grey on the belly. The back 
seems almost black, and the fins vary from brown to violet- 
grey. The iris is red, ringed or blended with yellow. The 
caudal fin is very broad and powerful, rounded at the angles 
and not divided into lobes. The other fins are all very 
