226 THE MYOLOGY OF THE RAVEN. 



the muscles in question, but only after the most con- 

 scientious study. Nor do I expect my opinion will 

 hold for all forms of birds, for as I have so often 

 stated on previous occasions, an enormous amount of 

 work still remains to clear up even these simple questions 

 in biology. 



Garrod and Forbes had chiefly to do with a limited 

 number of the plantar tendons, and I believe, so far as 

 they go, describe them correctly. Mivart has but little 

 to say about the musculature of these parts in Aves, and 

 I fail to find that any of these authorities speak of the 

 two sets of perforated tendons, with the exception of 

 Owen, who after describing a, flexor perforans digitorum : 

 a, flexor perforatus of the outer toe ; a, flexor perforatus 

 digitorum ; and as I say, a peroneus longus and medius, 

 says without any further explanation that " The second 

 and third toes have two perforated tendons ; one inserted 

 into the sides of the first, and the other into the sides 

 of the second phalanx" (Anat. of Verts., vol. ii. p. 

 109), but says nothing of the muscles from whence the 

 second set are derived. 



In view of the fact that a bird's hand and arm 

 have become completely subordinated to the purposes 

 of flight, and that its foot has become converted largely 

 into an instrument of prehension, is it not possible 



nay, quite probable that a higher specialization 

 of the muscles has, pari passu, become a necessity ? 

 and that the peronei muscles (beyond the peroneus 

 longus with its strikingly feeble insertion) are not 

 represented in these peculiarly modified vertebrates, 

 so far as their extremities are concerned ? These 

 peronei muscles are by no means constant, and are 



chiefly confined to the class Mammals. 



Such facts must have their weight in our myological 



