Chap. XII. Fishes. 331 



males of Plagiostomous fishes (sharks, rays) and of Chiruseroid 

 fishes are provided with claspers which serve to retain the 

 female, like the various structures possessed by many of the 

 lower animals. Besides the claspers, the males of many rays 

 have clusters of strong sharp spines on their heads, and several 

 tgws along " the upper outer surface of their pectoral fins." 

 These are present in the males of some species, which have 

 other parts of their bodies smooth. They are only temporarily 

 developed during the breeding-season ; and Dr. Giinther suspects 

 that they are brought into action as prehensile organs by the 

 doubling inwards and downwards of the two sides of the body. 

 It is a remarkable fact that the females and not the males of 

 some species, as of Raia clavata, have their backs studded with 

 large hook-formed spines. 1 



The males alone of the capelin (Mallot/rs vdlosus, one of 

 Salmonidae), 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, whilst she runs with great swiftness on the sandy beach, 

 and there deposits her spawn. 2 The widely distinct Monacanthus 

 scopas presents a somewhat analogous structure. The male, as 

 Dr. Giinther informs me, has a cluster of stiff, straight spines, 

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

 specimen six inches long were nearly one and a half inches in 

 length ; the female has in the same place a cluster of bristles, 

 which may be comrjared with those of a tooth-brush. In 

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

 possessed by the female of the last species, whilst the sides of 

 the tail in the female are smooth. In some ether 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 de- 

 scribed 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 direction, then to his accumulated 

 " materials for the nest, then back again in an instant ; and as 

 " she does not advance he endeavours to push her with his snout, 

 " and then tries to pull her by the tail and side- spine to the nest." 3 



1 Yarrell's 'Hist, of British 1871, p. 119. 



Fishes,' vol. ii. 1836, pp. 417, 425, 3 See Mr. R. Wariugton's in- 



436. Dr. Giinther informs me that teresting articles in 'Annals and 



the spines in R. clavata are peculiar Mag. of Nat. Hist.' Oct. 1852 and 



to the female. Nov. 1855. 

 ; The American Naturalist,' April 



