526 APPENDIX. 



above the other, and always destitute of teeth. The anterior pair of limbs is 

 developed into wings which, however, are not always capable of use in flight ; 

 the posterior serve as legs for the support of the body in an oblique or nearly 

 erect position. The body is covered with feathers of variable structure and charac- 

 ter, both in the young bird and the old. (The wings are apparently wanting in 

 some fossil species.) 



The following terms, English and Latin, are those most generally employed in 

 describing the external form of birds, and are principally as defined by Illiger. 

 In cases where there is no suitable English word in use, the Latin equivalent only 

 is given. The figure selected for illustration, drawn by Mr. R. liidgway, is that 

 of the common American robin [Turdus migratorius, L.), and will be familiar to 

 most students of ornithology. 



A. Body in General {Corpus). 



1. Feathers {Pluma). A dry elastic object, with a central stem at one end forming a hol- 



low horny tube implanted in the skin at its tip, the other feathered on opposite sides. 



2. Quills (Pennce). The large stiff feathers implanted in the posterior edge of the wing and 



in the tail. 



3. Plumage (Ptilosis). The general feathery covering of the body. 



4. Unfeathered {Implumis). A portion of skin in which no feathers are inserted. 



5. Upper parts {Notceum). The entire upper surface of the animal. (Sometimes restricted 



to the trunk.) 



6. Lower parts (Gastra?mn). The entire lower surface of the animal. (Sometimes restricted 



to the trunk. ) 



7. Anterior portion (Stethiceum). The forward part of the body (about half), both upper 



and under surfaces, including the chest. 



8. Posterior portion (Urceum). The hinder portion of the body (about half), including the 



abdominal cavity. 



B. The Head (Caput). 



9. Rill {Rostrum). The projecting jaws, one above the other, united by a hinge joint behind, 



and covered by a horny sheath, or a skin, and enclosing the mouth. 



10. Maxilla, or upper jaw {Maxilla). 



11. Mandible, or lower jaw {Mandlhula). 



12. Ramphotheca. The horny covering, or sheath of the jaws. 



13. Rhinotheca. The covering of the upper jaw. 



14. Gnathotheca. The covering of the lower jaw. 



15. Cere {Cera, or Ceroma). A skin at the base of the maxilla, in certain birds. 



(In birds without a horny sheath to the bill, the cere may be considered as 

 extending to its very tip.) 



16. Edges of bill {Tomia). The margins of upper and lower jaws where they come in 



contact. We have thus a 



17. Maxillary tomium, and a 



18. Mandibular tomium. 



19. Gape or Commissure {Commissiira). The junction of the tomia, or of the two bills. 



