Contributions to Bird-Anatomy and Classification. 13 



perforate those of the more superficial ^e^or j9er/ora^W5 (the 

 muscle, it will be remembered, joined by the tendon of the 

 amhiens) . Below the " ankle " the tendons of these muscles 

 run along the tarso-metatarse ; whatever their ultimate distri- 

 bution, they may be easily identified in this region, the flexor 

 longus hallucis being always external to, or superficial of, the 

 flexor perforans (or both) . In all the Passeres, as already 

 noticed by Sundevall (except in the Eurylsemidse, wicfe infra), 

 as well as in Upupa epops and perhaps one or two Ardeine birds, 

 these two tendons are quite independent of each other, so that 

 \ii\i.e flexor hallucis be artificially pulled no flexion (closing) of 

 the other digits takes place. This arrangement is represented 

 in fig. 6. In all other birds, however, the two tendons, during 

 some part of their course in the tarso-metatarse, are more or 

 less intimately connected together by a fibrous band or vin- 

 Fig. 6. Fig. 7. 



A typical Passerine foot Foot of Gallns hankiva 



(from P. Z. S. 1875, p. 347, fig. 9). (from P. Z. S. 1876, p. 341, fig. 1), 



V, Vinculum. 



