Morphology. 77 



retain in a dwindled and useless condition (Fig. u). 

 This is likewise the case in anthropoid apes ; but in 

 not a few other Quadrumana (e.g. baboons, macacus, 

 magots, &c.) degeneration has not proceeded so far, 

 and the ears are voluntarily moveable. 



(2) Panniculus carnosis. A large number of the 

 mammalia are able to move their skin by means of 

 sub-cutaneous muscle as we see, for instance, in a 

 horse, when thus protecting himself against the 

 sucking of flies. We, in common with the Quad- 

 rumana, possess an active remnant of such a muscle in 

 the skin of the forehead, whereby we draw up the 

 eyebrows; but we are no longer able to use other 

 considerable remnants of it, in the scalp and elsewhere, 

 or, more correctly, it is rarely that we meet with 

 persons who can. But most of the Quadrumana 

 (including the anthropoids) are still able to do so. 

 There are also many other vestigial muscles, which 

 occur only in a small percentage of human beings, 

 but which, when they do occur, present unmistakeable 

 homologies with normal muscles in some of the Quad- 

 rumana and still lower animals T . 



(3) Feet. It is observable that in the infant the 

 feet have a strong deflection inwards, so that the soles 

 in considerable measure face one another. This 

 peculiarity, which is even more marked in the embryo 

 than in the infant (see p. 153), and which becomes 

 gradually less and less conspicuous even before the 

 child begins to walk, appears to me a highly sugges- 

 tive peculiarity. For it plainly refers to the condition 



1 See especially Mr. John Wood's papers, Proc. R. S., xiii to xvi, and 

 xviii ; also Journ. Anat.',\ and iii. In this connexion Darwin refers 

 to M. Richard, Annls. d. Sc. Nat. Zoolg., torn, xviii, p. 13, 1853. 



