30 TSn DESCENT OF MAN 



economy can come into play, is perhaps intelligible by the 

 aid ot the hypothesis of pangenesis. But as the whole sub- 

 ject of rudimentary organs has been discussed and illustrated 

 in my former works,'* I need here say no more on this head. 

 Rudiments of various muscles have been observed in 

 many parts of the human body," and not a few muscles 

 which are regularly present in some of the lower animals 

 can occasionally be detected in man in a greatly reduced 

 condition. Every one must have noticed the power which 

 many animals, especially horses, possess of moving or 

 twitching their skin; and this is effected by the pan- 

 niculus carnosus. Remnants of this muscle in an efficient 

 state are found in various parts of our bodies ; for instance, 

 the muscle on the forehead, by which the eyebrows are 

 raised. The platysma myoides, which is well developed on 

 the neck, belongs to this system. Prof. Turner, of Edin- 

 burgh, has occasionally detected, as he informs me, muscu- 

 lar fasciculi in five different situations, namely in the axillae 

 near the scapulae, etc., all of which must be referred to the 

 system of the panniculus. He has also shown" that the 

 musculus sternalis or sternalis brutorum, which is not an ex- 

 tension of the rectus ahdominalis, but is closely allied to the 

 panniculus, occurred in the proportion of about three per 

 cent in upward of 600 bodies: he adds, that this muscle 

 affords "an excellent illustration of the statement that oc- 

 casional and rudimentary structures are especially liable 

 to variation in arrangement." 

 ^ Some few persons have the power of contracting the 

 superficial muscles on their scalps; and these muscles are 

 in a variable and partially rudimentary condition. M. A. 

 de OandoUe has communicated to me a curious instance of 



^ "Variation of Animals and Plants under Domestication," vol, '' 

 and 397. See also "Origin of Species," 5th edit. p. 535. 



^^ For instance M. Richard ("Annales des Sciences Nat^tiiiig a valuable paper, 

 1852, torn, xviii. p. 13) describes and figures rudimer-' ("-A-imuario della Soc. d. 

 "muscle p^dieux de la main," which he says is sQ"'''^l'ioh paper I am consid- 

 Another muscle, called "le tibial post^rieur," is-* discussions on this whole 

 Land, but appears from time to time in a more c# "GenereUe Morphologie," and 



*» Prof. W. Turner, "Proc. Royal Soc. Edi» 



