•244 



SCANDINAVIAN FISHES. 



M'orthy specific character. The definition of the species 

 grounded on the size and number of the scales of the 

 bod}^ is often liable to equally great uncertainty. True, 

 the scales on the caudal region are arranged in fairly 

 regular I'ows; but on the abdominal sides, in front of 

 the second dorsal fin, they generally become smaller 

 Mild smaller, and their arrangement more and more 

 irregular, the nearer they are to the front part of the 

 bod\-. This sometimes renders it a matter of some 

 ditticult}" to compute the numbei- of scales in a line 

 Ml(jng the sides of the body. In the following table, 

 liy which it should be possible to recognise the species 

 wliich have hitherto been established and adopted as 

 Ix'loiiffina: to the Scandinavian fauna, and which is also 

 intended to show their natural relationship, we have 

 endeavoured, as far as possible, to avoid tlie employ- 

 ment of such characters as may easily lead astray. 

 However, as we shall now sliow, tiie question of the 

 actual right of all these species to recognition is still 

 unsolved. Several of them are founded on an insigni- 

 ficant number of known specimens, and the variations 

 of such "s])ecies" are far too little known to admit of 

 their elucidation on scientific principles. 



^4 : Length of the peduncle of the tail at the 

 upper margin" about '/., that of the base 

 of the second dorsal fin. Least depth of 

 the tail more than 30 % of the length of 

 the head. Six rays in the first dorsal 

 fin. Vent situated in front of the middle 

 of the body. 



a: Number of scales in a transverse row 

 on the body at the besinninw of the 

 anal fin about 12, and in a row along 



the sides of the body about 40 Gobius niger. 



h: Number of scales in a transverse row 

 on the body at the beginning of the 

 anal fin about 7, and in a row along 



the sides of the body about 25.. Gobius Friesii. 



B: Length of the peduncle of the tail at the 

 upper margin about equal to the base of 

 the second dorsal fin. 

 a: Least depth of the tail more than 

 30 °'o of the length of the head or than 

 40 '/c, of the length of the peduncle 

 of the tail at the upper margin. 

 aa: Number of scales in a transverse 

 row on the body at the beginning 

 of the anal fin about 10 — 12, and 

 in a row along the sides of the 

 body about 40. Vent situated in 

 front of the middle of the body. 

 a: Seven rays in the first dorsal fin Gobius Jiavescens. 

 (i: Six (exceptionally five) rays 

 in the first dorsal fin. 



aa: Longitudinal diameter of 



the eye less than -/j of the 



distance from the first ray 



in the first dorsal fin to the 



first ray in tlie second... Gobius mic7'0fs. 



(ifi: Longitudinal diameter of 



the eye more than -/- of 



the distance from tlie first 



ray in the first dorsal fin to 



the first ray in the second Gobius pictus. 



bb: Number of scales in a transverse 



row on the body at the beginning 



of the anal fin about 6 — 8, and in 



a row along the sides of the bodv 



25—30. 



«; Seven rays in the first dorsal 

 fin. Vent situated in front of 



tlie middle of the body Gobius orca. 



/S; Six (exceptionally five) rays in 

 the first dorsal fin. 

 aa: Vent situated behind the 



middle of the body Gobius srorpioides. 



/J/J." Vent situated in front of 



the middle of the body.. Gobius Jeffreysii. 

 b: Least depth of the tail less than 30 % 

 of the length of the head or than 40 % 

 of the length of the peduncle of the 

 tail at the upper margin. Number of 

 scales in a transverse row on the body 

 at the beginning of the anal fin about 

 12 — 14, and in a row along the sides 

 of the body about fiO. Six (exception- 

 ally five) or seven rays in the first 

 dorsal fin. Longitudinal diameter of the 

 eye less than '/j of the distance from 

 the first ray in the first dorsal fin to the 

 first ray in the second, ^'ent situated 

 in front of the middle of tlie body... Gobius miiutfus. 



Among these recognised species we have first to 

 distinguish the deep-water forms, with larger eyes, 

 larger (more scattered) scales and more elongated (low) 

 body. To this division belong Gobius Friesii, orca, 

 scorpioides and Jeffreysii, the last three of Avhich we 

 have been able to examine only in one solitary specimen 

 the name of which could be fixed with certainty. With 

 this exception, these four species are given here on the 

 authority of other writers. We Avould also mention 

 here that the distinction between Gobius microps and 

 Gobius pictns has in many respects proved difficult to 

 fix. Remembering the account we have given abo\e 

 of the variation in the number of the rays in the first 

 dorsal fin, we consider it l)y no means improbable that 

 future researches may show the connexion between these 

 forms to be so close that the Scandinavian fauna at the 

 present time really contains onl)- five known species of 

 the genus, precisely those which, as early as 1838, were 



" Between the seeciiid dorsal and (lie eandal fins. 



