190 



THE FRESH-WATER FISHES OF EUROPE. 



Fig. 103. PHARYNGEAL TEETH OF TINCA 



VXJLGAKIS. 



osseous ray by the Austrian writers and by Von Siebold, but is ignored by 

 Dr. Giinther; the second ray is imperfectly developed. The longest rays of 

 this fin are equal to two-thirds of the height of the body. The anal fin 

 is not close to the vent ; it is as deep as the tail, and as long as the pectoral 

 fin. The fifth and sixth rays are the longest. The ventral fins are a little 



in advance of the beginning of the 

 dorsal; the first two rays are often 

 rudimentary ; sometimes the fin is as 

 deep as the dorsal is high ; but the 

 depth varies with sex. At first, accord- 

 ing to Von Siebold, the fins are alike 

 in male and female, but after develop- 

 ment of the reproductive organs has 

 taken place, the first ray becomes thick 

 in the male and very thin in the 



female. These fins reach back to the vent. The pectoral fins have thinner 

 rays, the first scarcely stronger than the others ; the longest are the fourth 

 to sixth, and they do not reach to the ventrals. The longest rays of the tail 

 fin are almost equal to those of the dorsal fin ; the tail is evenly rounded, with 

 a very slight emargination. 



The remarkably small scales shine through the thick greenish-brown 

 epithelium of the skin as a number of glistening golden points. There are 

 over a hundred on the lateral line. The scales are much longer than they 

 appear to be, for only their extremities are seen while they are still attached 

 to the fish. They are narrow, rounded at both extremities, marked with 

 numerous striae, which radiate longitudinally from a point near the base. 

 The concentric striae are very wavy, and arranged round the basal point. 

 There are from thirty-two to thirty-three scales above the lateral line, and 

 eighteen to twenty-five below, to the base of the ventral fin. The lateral 

 line at first descends in a curve from the operculum as far as the middle 

 of the body, and is then prolonged in a straight median line to the middle 

 of the tail. The mucus-canals are short and cylindrical. The mucus-canal 

 system of the head is well developed, with numerous pores. There are twenty- 

 three or twenty-four of these apertures on the pre-operculum and lower jaw. 

 They are even more abundant on the sub-orbital ring, and not less numerous 

 on the anastomosing branches of the frontal and occipital region. The 

 secretion of mucus from these canals and the lateral line is so great that 

 it forms a thick stratum over the body, and renders the Tench as slippery 

 as an Eel. 



The colour of the Tench varies with the water. When it lives in muddy 



