Limbs of Vertebrate Animals. 3 1 



with the " spurious or bastard feathers," while the rest 

 of the arm is represented by the two other segments of 

 the limb, the fore arm by the middle segment which 

 supports the feathers called " wing coverts " or " secon- 

 daries," the arm by the innermost segment which carries 

 the feathers to which the name of " scapularies" is given. 

 The hand, and the whole limb belonging to it, are 

 hidden under the feathers, except in birds like the pen- 

 guin where the wing is represented by a paddle or fin, 

 covered by mere vestiges of feathers, which at first 

 glance resemble scales, but the component parts, though 

 rudimentary, are easily identified. Three distinct fingers 

 fused more or less completely together as one bone, 

 are always present, and, so are the matacarpal bones 

 belonging to them. There are also distinct carpal 

 bones, usually not more than two in number. The 

 fingers are the 2nd, 3rd, and 4th, the 3rd being largely 

 developed and having two phalanges, the 2nd and 4th 

 being quite stunted, and having only one phalanx. 

 Usually these fingers are completely hidden under the 

 integument : sometimes from the 2nd in the Apteryx 

 and from the 3rd in the ostrich a claw protrudes 

 from one or other of them. In all cases the prin- 

 cipal feathers or " primaries " are supported by the 3rd 

 finger, and the metacarpal bone belonging to it : in all 

 cases, the " spurious or bastard feathers " are attached to 

 the stunted index or 2nd finger : in no case does the 

 stunted 4th finger take any share in the feather-bearing 

 office of the 3rd and 2nd. 



And so too in the simpler appendages which ob- 

 viously take the place of the fore limb in the tran- 

 sitional mudfish or Lepidosiren (Protopterus annec- 

 lans] which is neither fish nor reptile, and in the 

 ichthyomorphous or perenni-branchiate batrachians. In 



