[B5]

June 21 - 67. Fishes.

Günther says than most male fishes, such as tench, perch, roach, during breeding season are brighter coloured than the females. (In the whole genus Callionymus especially in C. lyra (Gobiidæ) [illeg] 2 p. 247 the male is coloured with spots far more brilliantly than the female; the first dorsal fin is prodigiously produced & brightly striped; so that they differ almost as much as sexes in the Peacock: The young male resembles in structure & colour the female. Hence G. (Cat. of Fishes in Brit Mus. vol. 3 1861. p. 141) says case is strictly like that of gallinaceous birds. In several species of Blenny the

[B6]

Jun 21-67

male is brighter coloured & has a crest of membrane on the head which is not a fin & of which the female has no trace; but in some species both sexes have this crest; another analogue with birds.

In scarus (coral-feeder) there are wonderful diversities of colour, but it is not positively known that the splendid green fishes are the males. Wallace thinks that the colours are protective on account of corals but I doubt, he says no tropical f. w. fishes are bright coloured. See Mc.Clellan.

G. shewed me male & female of Labrus mixtus in which female is brighter coloured than male with 3 or 4 quite black spots on back which are absent in male; another analogue with birds.

(over

[B6v]

G. says there are many cases in which the male presents structural differences from female, solely for ornament.

These many fish cases make one doubt Wallace's view of the importance of nests:

In stickle-back it is the male which is gaudily attired & he watches & guards the nest.

Yarrell male salmon p. 10 male coloured on cheeks Hook on lower jaw

Vol. 2

p. 11 spawning takes several days. ( [illeg] 2 males seen to follow same female)

12 similar markings that prove salmon wild [illeg]

p. 35 colour of Bull-trout

In such a genus as Labrus, so brilliantly coloured, in which sexes of same differ widely were as shy of  [4 words illeg] see Distribut.

[Descent 2: 14, n20: "Yarrell, 'British Fishes,' vol. ii. 1836, p. 10, 12, 35."]