!)2 



(»PE 



D 



Fig. 32.— Diagrams exhibitins the more important modes of distribution of the deep plantar 

 tendons in Euornithes. A^ nomopelmous (schizopelmous) ; B, synpelmous (desmopelmous) ; 

 C, antipelmous ; D. lieteropelmous ; jlh, flexor longus hallucis ; fpd, flexor perforans digitorum 

 V, vinculum. 1 to XV, 1st to 4th toes. (Alter Stejneger). 



The digits of birds are arranged in several different orders. 

 The usual type with three toes forwards and one backwards 

 is termed anisodactylous ; that with the first and fourth 

 backwards and second and third forwards, is syndactylous- 

 When the first and second are directed backwards and the 

 third and fourth forwards the arrangement is termed he- 

 terodactylous ; and when all four are directed forwards the 

 foot is said to be pamprodactylous. The fiexor tendons of 

 the toes are arranged differently in these different digital 

 arrangements, although not always identically in the same. 

 The arrangement usual ivi the anisodactylous foot is the 

 .schizopelmous system, where the flexors of the digits 2-3-4 

 have a common stem, while that of digit 1 is distinct. 

 In some anisodactylous feet, however, all the- flexors or ten- 

 dons are more or less fused ; this is the desmopelmous sys- 

 tem ; it occurs also in many zygodactylous feet. In an- 

 other type of zygodactylous foot (that of the Picoidei) we 

 have the antipelmous arrangement. Here all the tendons 

 are fused excepting that of third, which is distinct. Finally 

 in the heterodactylous foot we have the heteropelmous 



