FISHES. 



381 



appendages which appear to be of no more use ix) him for 

 the ordinary purposes of life than are the tail feathers to 

 the peacock. I am indebted for most of the following 

 facts to the kindness of Dr. Giinther. There is reason 

 to suspect that many tropical fishes differ sexually in color 

 and structure; and there are some striking cases with our 

 British fishes. The male Callio^iymns lyra has been called 

 the gemmeous dragonet ^^ from its brilliant gem-like colors/' 



Fig. 29. Callionymus IjTa Upper figure, male ; lower figure, female. 

 N. B. The lower figure is more reduced than the upper. 



When fresh caught from the sea the body is yellow of 

 various shades, striped and spotted with vivid blue on the 

 head; the dorsel fins are pale brown with dark longitudinal 

 bands; the ventral, caudal and anal fins being bluish-black. 

 The female, or sordid dragonet, was considered by Lin- 

 naeus and by many subsequent naturalists as a distinct 

 species; it is of a ding}^ reddish-brown with the dorsal fin 

 brown and the other fins white. The sexes differ also in 

 the proportional size of the head and mouth and in the 

 position of the eyes;* but the most striking difference is 

 the extraordinary elongation in the male (fig. 29) of the 



*I have drawn np this description from Yarrell's "British 

 Fishes," vol. i, 1836, pp. 261, 266. 



