. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XVII.] MEANS OF DEFENCE. 253 surfaces would, however, if the head were held a little laterally, serve as an excellent guard; and hence, per- haps, it is that in old animals they " are generally broken off, as if by ; 36 Here, then, we have the curious case of the upper tusks of the Babirusa regularly assum- ing, during the prime of life, a structure which apparently renders them fitted only for defence; wh


. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XVII.] MEANS OF DEFENCE. 253 surfaces would, however, if the head were held a little laterally, serve as an excellent guard; and hence, per- haps, it is that in old animals they " are generally broken off, as if by ; 36 Here, then, we have the curious case of the upper tusks of the Babirusa regularly assum- ing, during the prime of life, a structure which apparently renders them fitted only for defence; while in the Euro- pean boar the lower and opposite tusks assume in a less degree and only during old age nearly the same form, and then serve in like manner solely for iiiwi i run i inn oravi uw (wrowuw ui mi ii redtK '-d nciile. the chiiructi iH ol tin- mule i Iii the wart-hog (P/ntcnr/iocrus a-thhtpirus, Kig. the tusks in the upper jaw of the male ourve upward dur- ing the prime of life, and, from being pointed, serve ai for midahlc weapons. The tusk- in the lower ja* sre sharper ihan thorn- in the upper, hut from their Bhortnesi it leemi hardly possible thai they can be a Bed as weapons of at tack. They must, however, greatly itrengthen those in the â ⢠Soe Mr. Wallace'* Intcrontlng account of thlft animal, 1 Thi Kslsj Archipelago,' 1800, vol. I. p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Darwin, Charles, 1809-1882. New York: D. Appleton and Company


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Keywords: ., bookcentury1900, booksubjectevolutionbio, booksubjecthumanbeings