APPENDIX. 531 



Legs (Coiifinued). 



116 Toes (Digid). The, usually foiir, sometimes three, very rarely two, articulated portions 



of tlie leg hinged on the lower extremity of the tarsus. When all four are present, one 



is usually behind, sometimes two before, and two behind. 



117. Top of toes (Acrodaciyluin). The upper surface of the toes individually. 



118. Soles of toes (Hypodaclijlum). The lower or plantar surface of the toes indi- 



vidually. 



119. Side of toes {ParadacUjlum). The sides, in any way distinguished from the 



soles. 



120. Phalanges. The several bones composing a toe. 



121. Claw (Unfjues). The horny ti|)s sheathing the last joint of the toes. 



122. Claw joint {Rhizonychium). The terminal bone of the toe, carrying or armed 



with the claws. 



123. Pads ( Tifluri). The swellings or bulbs ou the under side of the phalanges. 

 Tliose Toes are 



124. Anterior which are directed forwards; 

 12.5. Posterior, directed backwards ; 



126. Exterior, on the outer side of the foot ; 



127. Interior, on the inner side of the foot ; the 



128. Middle toe is the central of three toes directed forwards. 



129. Hind toe (Hallux). The single toe directed backwards. This is horaologically 



the first or great toe directed backward. It is 



130. Insistent (insmtms), when the tip at least touches the ground, but the base raised 



above the level of the rest ; 



131. Incumbent (/yicumAews), when its whole under surface touches the ground; and 



132. Elevated {elevatus ; amotns), when raised so high that the tip does not touch the 



ground at all. 



133. Unarmed toe [Digitus muticus). Toe without a claw. The tarsus is unarmed 



when without a spur. 



134. Fringed toe (Digitus lomatimis). A lateral membranous margin to the toes. This 

 13.5. Fringe (Z.oMa) may be 



138. Continuous (continuum), or 



137. Lobed or Scolloped (hbatum). 



138. Membrane (Pa/ama). A skin either soft or covered with scales or feathers con- 



necting two adjacent toes together at the base, and sometimes extending to or 

 beyond their tips. The foot so constructed is called 



139. Palmate (palmatus) when the anterior toes only are so connected and 



141. Oared (Steganopus), where all the toes, including the hinder, are so connected in 



the cormorants, etc. The feet may be half, or semipalmate ; entirely or toti- 

 palmate. 



Note. In the usual an-angement of the toes, of three before and one behind, tlie hinder corresponds 

 to the great toe of man, or the first; the inner anterior is the second; the middle is the third; and the 

 outer is the fourth. When the toes are in pairs or two before and two behind, it is the outer or fourth 

 toe that is turned backwards, as is the woodpeckers. In the Trogons, however, the inner toe is revered. 

 With scarcely an exception in birds, the hinder or first toe has two joints; the inner (2(1) has three; the 

 middle (3d) has four; and the outer (4th) has five, or a formula of 2.3.4.-5. In the typical Capri- 

 mulgidce the outer toe has only four phalanges the formula being 2.3.4.4. Finally, in some CypselidcB 

 ( Cypselus and Pnnytila), we have the middle and outer toes with three joints only each, the formula be- 

 ing 2.3.3.3. When there are but three toes, the hinder or first is wanting; the ostrich (Slruthio) lias but 

 two toes, lacking the first and second. 



