432 THE DESCENT OF MAN 



Bides of the body. It is a remarkable fact that the females 

 and not the males of some species, as of Raia clavaia, have 

 their backs studded with large hook-formed spines." 



The males alone of the capelin {Mallotus villosus, one 

 of Salmonidse) are provided with a ridge of closely set, 

 brush-like scales, by the aid of which two males, one on each 

 side, hold the female, while she runs with great swiftness 

 on the sandy beach, and there deposits her spawn.' The 

 widely distinct Monacanihus scopas presents a somewhat 

 analogous structure. The male, as Dr. Giinther informs 

 me, has a cluster of stiff, straight spines, like those oi 

 a comb, on the sides of the tail; and these in a specimen 

 six inches long were nearly one and a half inch in length ; 

 the female has in the same place a cluster of bristles, which 

 may be compared with those of a toothbrush. In another 

 species, M. peronii, the male has a brush like that possessed 

 by the female of the last species, while the sides of the tail 

 in the female are smooth. In some other species of the 

 same genus the tail can be perceived to be a little roughened 

 in the male and perfectly smooth in the female; and lastly, 

 in others both sexes have smooth sides. 



The males of many fish fight for the possession of the 

 females. Thus the male stickleback {Gasterosteus leiurus) 

 has been described as "mad with delight" when the female 

 comes out of her hiding-place and surveys the nest which 

 he has made for her. "He darts round her in every direc- 

 tion, then to his accumulated materials for the nest, then 

 back again in an instant; and as she does not advance 

 he endeavors to push her with his snout, 'and then tries 

 to pull her by the tail and side-spine to the nest." ^ The 

 males are said to be polygamists; * they are extraordinarily 



' See Tarrell's "History of British Fishes," volume ii., 1836, pp. 41t, 425, 

 and 436. Dr. G-iinther informs me that the spines in R. clavatd are peculiar 

 to the female. 



2 "The Am. Naturalist," April, \S11, p. 119. 



* See Mr. R. Warington's interesting articles in "The Annals and Magazine 

 of Natural History," October, 1852, and November, 1855. 



^ Noel Humphreys, "River Gardens," 1867. 



