[118r]

(Ch. 9.)

366

*(14) (1) Anatomy of Expression. p. 137, 139. It is not surprising that the corrugator supercilii should have become shd be much more developed in man than in the anthropoid apes; for it is brought into incessant use action by man him under various circumstances, & will have been strengthened & modified by the inherited effects of use. We have seen how important a part it plays, together with the orbiculars, in protecting the eyesfrom being too much gorged with blood during violent expiratory movements. — When the eyes are closed as violently quickly & as forcibly as possible to save themfrom being injured by a blow this muscle is used. With man, savages or other men, whose gr heads are [text excised] with most savages, the contracted eyebrows are

[Expression, pp. 222-3, n1: "Anatomy of Expression,' pp. 137, 139. It is not surprising that the corrugators should have become much more developed in man than in the anthropoid apes; for they are brought into incessant action by him under various circumstances, and will have been strengthened and modified by the inherited effects of use. We have seen how important a part they play, together with the orbiculares, in protecting the eyes from being too much gorged with blood during violent expiratory movements. When the eyes are closed as quickly and as forcibly as possible, to save them from being injured by a blow, the corrugators contract. With savages or other men whose heads are uncovered, the eyebrows are continually lowered and contracted to serve as a shade against a too strong light; and this is effected partly by the corrugators. This movement would have been more especially serviceable to man, as soon as his early progenitors held their heads erect. Lastly, Prof. Donders believes ('Archives of Medicine,' ed. by L. Beale, 1870, vol. v. p. 34), that the corrugators are brought into action in causing the eyeball to advance in accommodation for proximity in vision."]