28 Leach, The Myology of the Bell-Magpie. [„t^''"juiy 



the tibial cartilage and through the hypotarsus near the inner 

 side. It runs directly down the back of the tarso-metatarsus, 

 between the bone and the tendon of the flexor longus hallncis (47). 

 In this part the tendon develops a flattened bony rod. At the 

 lower end of the tarsus the tendon trifurcates, forming three 

 strong tendons, which run one to each toe. Each runs in a deep 

 groove on the under side of the toe to be inserted into a tubercle 

 at the base of the ungual phalanx. Each tendon passes through 

 or perforates the tendon of muscles inserted on the more 

 proximal phalanges of the toes. 



The branch on the index toe perforates the tendons of the 

 fl,exoY perforatiis indicts secundus pedis (116) and the flexor 

 perforatus indicis primus pedis (121) — that is, the tendon of muscle 

 116 wraps round or ensheathes the tendon of 122 for some 

 distance and then bifurcates into two slips, one of which is 

 inserted on either side of the second phalanx of the index. The 

 tendon of 121 is wrapped round both 116 and 122 for a short 

 distance. It bifurcates, and the slips are inserted, one into either 

 side of the basal phalanx. Both 116 and 122 perforate 121, while 

 116 is perforated by 122. Similarly, on the medius toe 122 per- 

 forates 119 and 120, while on the annularis toe 122 perforates 

 118, which, however, after ensheathing 122 and bifurcating, and 

 having two slips inserted into either side of the basal phalanx, 

 runs on (still ensheathing 122) to bifurcate again and be inserted 

 on either side of the third phalanx. As the three branches of the 

 tendon of the flexor perforans digitorum profundus (122) perforate 

 other tendons, the word " perforans " is part of the name of this 

 muscle. The arrangement of the tendons of these flexor muscles 

 is of much taxonomic value. In the birds under examination 

 the tendon of the flexor perforans digitorum profundus (122) passes 

 through the hypotarsus to the outer side. It then passes down 

 the middle line, becomes flattened and ossified, passing under 

 the tendon of the flexor longus hallucis (117), but without being 

 joined by a vinculum or loop to that muscle. This relation 

 holds in all Passerine and some Picarian birds. Professor 

 Sundevall and Professor Garrod found these deep plantar tendons 

 of much value as a guide to classification. 



THE MUSCULATURE OF THE TRUNK. 



The muscles of the freely movable neck are well developed : 

 on the other hand, the muscles of the rigidly supported back region 

 are poorly developed. Twelve muscles were described by 

 Shufeldt for the American Raven. The Strepera and other birds 

 under notice agree closely in the size and arrangement of these 

 muscles. 



The careful descriptions and full details given by Shufeldt 

 render comparison of the Strepera with the Raven a comparatively 

 simple task, though the dissection of the neck muscle is by no means 

 an easy one. The neck muscles have been named by Shufeldt 

 as follows : — 



