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SEXUAL DIMORPHISM 



also elongated to a less extent posteriorly. The male is 

 larger than the female. We might infer by analogy that the 

 male in this species practises definite habits and gestures of 

 courtship, and Mr. Saville Kent proved that this was the case 

 by observations, of which he gave a description in Nature in 

 1873 (vol. viii. p. 264). His remarks are quoted by Darwin 

 in his Descent of Man, etc., p. 336. Mr. Saville Kent also 

 describes the process of pairing of these fishes in one of the 

 Handbooks of the International Fisheries Exhibition (vol. i., 

 1883, p. 128). The account there given is as follows : 



" The male, resplendent in his bridal livery, swims leisurely 

 round the female, who is reclining quietly on the sand, his 

 opercula distended, his glittering dorsal fins erect, and his every 

 effort being concentrated upon the endeavour to attract the 

 attention and fascinate the affections of his mate. . . . The 

 female, at first indifferent, becomes at length evidently dazzled 

 by his resplendent attire and the persistency of his wooing. 

 She rises to meet him, the pair so far as is practicable with 

 fishes rush into each other's arms, and with their ventral 

 areas closely applied ascend perpendicularly towards the 

 surface of the water. In connection with these manoeuvres, 

 it may be safely predicted that the ova are extruded and 

 fertilised, but in the limited depth of water of an aquarium 

 tank the matrimonial tour cannot apparently be sufficiently 

 prolonged to ensure the consummation of this act, the fish, 

 after reaching the surface, being projected by their previously- 

 gained impetus slightly above it, when, falling apart, they 

 sink slowly to the bottom, and the process, after short inter- 

 vals, is repeated." 



My friend, Mr. E. W. L. Holt, has recently been able to 

 make a careful investigation of the phenomena in the Marine 

 Biological Laboratory at Plymouth, and has published an 

 excellent account of his observations in Proc. Zool. Soc. of 

 April 19, 1898. From Mr. Holt's paper I take the facts 



