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Show 126 THE DESCENT OF 1\IAN. PAnT I. In man the canine teeth are perfectly efficient instruments for mastication. But their true canine character, as Owen 39 remarks, "is indicated by the conical form "of the crown, which terminates in an obtuse point, is " convex outward and flat or sub-concave within, at the "base of which surface there is a feeble prominence. " The conical form is best expressed in the 1\ielanian " races, especially the Australian. The canine is more " deeply implanted, and by a stronger fang than the " incisors." Nevertheless this tooth no longer serves man as a special weapon for tearing his enemies or prey; it may, therefore, as far as its proper function is concei ·ned, be considered as rudimentary. In every large collection of human skulls some may be found, as Hackel 40 observes, with the canine teeth projecting considerably beyond the others in the same manner, but in a less degree, as in the anthropomorphous apes. In these cases, open spaces between the teeth in the one jaw are left for the reception of the canines belonging to the opposite jaw. An interspace of this kind in a Kaffir skull, figured by Wagner, is sm:prisingly wide.41 Considering how few ancient skulls have been examined in comparison with recent skulls, it is an interesting fact that in at least three cases the canines project largely; and in the Naulette jaw they are spoken of as enormous.42 brata, that chiefly led me to the above conclusion. This extraordinary fact of their regrowth remains inexplicable, if the belief in reversion to some extremely remote progenitor must be rejected. I cannot, however, follow Prof. Gegenbaur in supposing that additional digits could not reappear thr?ugh ~evers ion, without at the same time other parts of the skeleton bemg Simultaneously and similarly modified; for single characters often reappear through reversion. 39 ' Anatomy of Vertebrates,' vol. iii. 18G8, p. 323. 40 'Generelle Morphologic,' 1866, B. ii. s. clv. 41 Carl Vogt's 'Lectures on Man,' Eng. translat. 1864, p. 151. 42 C. Carter Blake, on a jaw from La Naulette 'AnthropoloO', Review,' 1867, p. 295. Schaaffhnusen, ibid. 1868, p. 426. "' CnAI'. IV. MANNER OF DEVELOPMENT. 127 The males alone of the anthropomorphous apes have their canines fully developed; but in the female gorilla, and in a less degree in the female orang, these teeth project considerably beyond the others; therefore the fact that women sometimes have, as I have been assured, considerably projecting canines, is no serious objection to the belief that their occasional great development in man is a case of reversion to an ape-like progenitor. He who rejects with scorn the belief that the shape of his own canines, and their occasional great development in other men, are due to our early progenitors having been provided with these formidable weapons, will probably reveal by sneering the line of his descent. For though he no longer intends, nor bas the power, to use these teeth as weapons, he wm unconsciously retract his "snarling muscles" (thus named by Sir C. Bell) 43 so as to expose them ready for action, like a dog prepared to fight. Many muscles are occasionally developed in man, which are proper to the Quadrumana or other mammals. Professor Vlacovich 44 examined forty male subjects, and found a muscle, called by him the ischiopubic, in nineteen of them ; in three others there was a ligament which represented this muscle; and in the I'emaining eighteen no trace of it. Out of thirty female subjects this muscle was developed on both sides in only two, but in three others the rudimentary ligament was present. This muscle, therefore, appears to be much more common in the male than in the female sex ; and on the principle of the descent of man from some lower form, its presence can be understood ; for it has been detected in several of the lower animals, and in all of 43 'The Anatomy of Expression,' 1844, p. 110, 131. 44 Quoted by Prof. Canest1·ini in the' Annuario,' &c., 1867, p. 90. |