214 THE MYOLOGY OF THE EAVEN. 



we have described for them above, as they exist in the 

 Raven. We have good views of them in Fig. 62 bis of 

 the present work. Several years ago I devoted no little 

 attention to the myology of Geococcyx, and published 

 my observations thereon in a number of places. The 

 bird, as is well known, occurs on the Pacific coast region 

 of the United States, and presents much of interest in 

 its anatomy. It is a big Ground Cuckoo with affinities 

 in other directions. 



To become impressed w-ith the gTcat numljcr of 

 changes to which this muscle is subject, we can do no 

 better than to read Professor Mivart's account of it, as w' e 

 find it among other representatives of the Vertel:)rata. 



This eminent anatomist tells us that " the tihialis 

 anticus, even in Anthropoid Apes, may have the part 

 ffoing to the hallux so distinct as to l)e reckoned a 

 distinct muscle— sometimes called the abductor longus 

 haUucis. It may be uncpiestionably double, as in the 

 Echidna. It may have a double origin and single 

 insertion, as in the Agouti. It may be inserted into 

 the second metatarsal, as in Hyrax ; and may be 

 altogether wanting, as in the Pig. It is inserted into 

 the tarso-metatarsal bone in Ijirds, and is situate 

 quite on the inner aspect of the leg in Cliameleo. It 

 exists down to the Urodeles, being apparently doul)le 

 even in Menobranchns. It may arise from the femur, 

 as in the Frog" (Elem. Anat., p. 351). 



Owen also found the tibialis anticus overlapped 

 by the peroneus, and arising partly in common with 

 that muscle, " and partly by sejiarate short tendinous 

 threads from the outer part of the head of the tibia ; it 

 gradually becomes narrower, and finally tendinous tw^o- 

 thirds of the way down the leg ; its strong tendon 

 glides through the oblique pulley in front of the distal 

 end of the tibia, expands as it passes over fhe ankle- 



