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Show f SEXUAL SELECTION. ORA PT Ell XII. SECONDAIW SEXUAL CrrAnACTEn OF FrsnEs, Ali1PIJIDTANS, A~D HEP'l'ILES. FJsrrEs: Courtship and bat.tles of the males- Larger size of tlw females- Males, bright colours and ornamental appendages; other strange characters- Colours and appendages acquired by the males during the brcetling-scason alone- Fishes with both sexes brilliantly coloured -l)rotcctive colonrs- 'l'he less conspicuous colours of the female cannot be accounted for on the principle of protection- Male fishes building nests, and taking charge of the ova and young. .AMPHIDIANS: Differences in strnctnre and colour between the sexes- Vocal organs. REP' l'nES: Chelonians- Crocodiles- Snakes, colours in some cases protective- Lizards, battles of- Ornamental appendag<sStrange differences in structure between the sexes- Colours -Sexual differences almost as great ns with birds. vV E have now anived at the great sub-kingdom of tho Vertebrata, and will commence with the lowest class, namely Fishes. ~rhe males of PJagiostomous :fishes (sharks, rays) and of Cbimmroid :fishes are provided with claspers which serve to retain the female, like the various structures possessed by so many of the lower animals. BesiJes the claRpers, the males of many rays have clusters of strong sharp spines on their head·, and several rows along " the upper outer surface of their pectoral fins." These are present in the males of some species, which have the other parts of their bodies vor.. .. n. B |
