222 THE MYOLOGY OF THE RAVEN. 



portion of it developing a tendon about half-way down, 

 which is concealed by the carneous fibres which overlie it. 

 This tendon passes round beneath the trochlea for the 

 fourth toe, and is really inserted on the underside oftlie 

 basal joint of this digit at its proximal extremity ; so 

 that in the case of this toe it seems as though it would 

 act almost as a flexor. With the second and third toes, 

 however, the carneous fibres of the muscle under con- 

 sideration are continued all the way to the trochlese, 

 where they terminate, in either case, in a strong, flat 

 tendon, which passing over the joint is inserted on the 

 upper side of the proximal extremity of the basal joint. 

 Here, of course, the muscle acts (in the case of the second 

 and third toes) as an auxiliary to the long extensor. 



Not a little room is here open to us for speculation as 

 to how the tendon of this short extensor in the case of 

 this fourth toe exactly came to assume its present point 

 for insertion, as the digit gradually and finally became 

 permanently reversed. Indeed, the high development 

 of this short extensor in Geococcyx over the vast majority 

 of the class is, too, an interesting fact ; and did the 

 reversion of the digit precede or follow the muscular 

 development ? No doubt the completeness of the latter, 

 and its perfection for an avian type, has come about as 

 a demand on the part of the habits of the bird itself and 

 its marvellous fleetness of foot. 



The muscles of the leg thus far dissected out should 

 now be carefully examined, particularly in regard to their 

 relations, and the relations and passage of their tendons. 

 They should next be removed close up to their origins 

 and insertions, and all superfluous tissue removed, as fat, 

 the vessels and nerves, and fascia and connective tissue- 

 leaving the muscles at the back of the limb perfectly 

 clean, and in as favourable condition to study as possible. 

 Next the podotheca of the tarso-metatarsus and 



