EXPLANATION OF PLATES. 



749 



Fig. 4. Niciitant Membrane folded up. 

 Fig. 5. Anterior View of the Eye-ball. 



Fig. 6. Posterior View of the Eye-ball. 



a, pyramidal muscle, of which the ten- 



don is attached to the nictitant 

 membrane. 



b, quadratus muscle. 



c, rectus superior. 



d, rectus inferior, 



e, rectus posticus. 

 /, rectus anticus. 



ff, obliquus superior. 

 h, obliquus inferior. 



Fig. 7. Lateral Vieiv of the Eye-ball. 



a, a, a, posterior surface. 



c, c, anterior part of sclerotica. 



b, b, margin of sclerotica. 



b, b, b, cornea, hemispherical. 



Fig. 8. Circle of Sclerotic Bones. 



a, inferior central bone. 



c, superior central bone. 



Fig. 9. Section of the Eye. 



a, a, sclerotic coat. 



b, b, choroid coat and pigmentum. 



c, ciliary circle. 



d, lens. 



e, e, iris. 



f, cornea. 



ff, optic nerve. 

 h, pecten. 



Fig. 10. The Lens. 



a, viewed laterally. 



b, seen from before. 



PLATE XVIII. Brain, Nasal Cavity, and Organ of Hearing 

 in the Brown Buzzard, Buteo vulgaris. Ear of Falcon. 

 Natural she. 



Fig. 1. Section of the Head of a 

 Buzzard, 

 a, b, c, d, section of skull, 



a, b, cerebellum. 



b, e, cerebrum. 

 e, optic lobe. 

 /, ff, pharynx. 



h, tongue. 



i,j, entrance of nasal passage. 

 j, k, median outline of palate. 

 /, nostril. 



m, n, 0, upper, middle, and lower tur- 

 binated bones. 



2), m, olfactory nerve. 



e, m, k, branch of fifth pair. 



Fig. 2. Skull of Buzzard, shewing the 

 Internal Ear, 



a, b, external aperture of ear. 



a, b, c, meatus externus, slit open. 



d, tympanum, 



e, muscle of lower jaw. 



f, g, h, semicircular canal. 

 i, vestibule. 



PLATE XIX. Respiratory Organs of Vultures, Hawks, and 

 Owls. Natural size. 



Fig- 1. Lower i)art of the Trachea of 



the Turkey Buzzard, Cat hartes Aura, 

 a, b, trachea, 

 c, inferior larynx. 



d, e, bronchi, membranous in a great part 



of their extent. 

 /, g, contractor muscles, ending in the 



sterno-tracheales. 



