1898.] BBBBDIN-G OF THE DEAGOKET. 283 



In connection with the preceding remarks, and also in ' Nature ' 

 (viii. 1873, p. 264), the author draws a comparison between tlie 

 secondary characters and courting behaviour o£ the male Oallio- 

 nymus and those of birds, which has been dignified by a reference 

 in Darwin's ' Descent of Man.' With regard to his account of 

 the pairing, it appears to be of a popular character, and, as the 

 subject is rather a delicate one, any criticism of its inadequacy 

 would be ungracious. If, however, I may judge from my own 

 experience, the account is so inaccurate in some details of im- 

 portance as to warrant a full redescription. 



II. Secondary Sexual Characters. 



It is now matter of common knowledge that, while young 

 Dragonets of either sex closely resemble each other both in colour 

 and conformation \ the male acquires, as its size increases, very 

 well-marked secondary sexual characters. It will be convenient 

 to briefly recapitulate the most striking differences, since these 

 will be found to play an important part in the behaviour of the 

 two sexes when pairing. 



In the female, throughout life the first dorsal fin is very short. 

 The second dorsal and the anal are of moderate proportions, their 

 posterior rays not being produced in such a manner as to reach 

 the caudal fin when depi-essed. The proportions of the head 

 undergo no marked metamorphosis. The genital aperture is at 

 no time produced into an elongated papilla. The colours of the 

 dorsal surface are brown or reddish brown, barred and mottled 

 with lighter and darker markings, and closely resembling the 

 bottom on which the fish may be resting. In young examples 

 on bright gravel the general colour may be diversified with purple, 

 green, and crimson. The veuti-al surface is devoid of pigment. 



The male, on the contrary, acquires with growth a more elon- 

 gated snout. The first dorsal fin becomes greatly elongated. The 

 second dorsal and the anal increase in size, especially their 

 posterior rays, which ultimately reach, when depressed, beyond 

 the origin of the caudal fin. There is a distinct genital papilla, 

 visible even in specimens only two inches in length, and 

 conspicuously elongated in large fish. The metamorphosis of the 

 head and fins appears to be of a gradual nature, though perhaps 

 more rapidly accomplished during the later period of growth. It 

 is not constantly related, in its ulterior development, to a fixed size, 

 nor to the attainment of sexual maturity. 



Pari passu with these structural differentiations appears a 

 striking change in the coloration. While the back retains the 

 marbled brown markings, the front and sides of the head, the sides 

 of the trunk, and the pelvic, dorsal, and caudal fins become decorated 

 with yellow and blue bands. I need not particularize these since the 

 drawing exhibited (Plate XXVI.) gives an accurate representation 



1 Inconspicuous differences exist from an early age (Fries, cf. Smitt, Hist. 

 Scand. Fish. ed. 2, i. p. 277). 



