154 PRACTICAL ORNITHOLOGY. 



minute apertures at the inner angle, which lead to a short duct 

 that conveys it to the nasal cavity. The Harderian gland is 

 larger, composed of a cluster of lobules or mucous follicles, and 

 is situated near the inner angle of the eye. Its fluid, which is 

 poured out by a single duct opening beneath the nictitant mem- 

 brane, also serves to moisten the eye. 



The Organ of Smell. — Let us now make a vertical section 

 of the head, in the direction of its middle line. We thus obtain 

 a view of the brain, the walls of the cranium, the septum be- 

 tween the eyes, the cavity of the nose, and the cells of the man- 

 dible, together with some other parts. The olfactory or first 

 pair of nerves are those by which the impressions of odorous 

 particles are conveyed to the brain. Their filaments are dispersed 

 over a delicate vascular membrane, which lines the interior of 

 the nose, and is enlarged by being extended over certain pro- 

 minences named the turbinated bones. 



In this section then, Plate XVIII, Fig. 1, we observe the 

 walls of the cranium, varying greatly in thickness, abed; 

 the brain, divided into the cerebellum situated below and 

 seeming to form the larger portion, from atob; the cerebrum, 

 or upper portion b c ; and the optic lobe in front, between 

 these two portions, e. The cerebrum is by far the largest por- 

 tion of the brain, it being more extended in breadth than the 

 cerebellum. Besides these parts are seen : the pharynx or 

 passage from the mouth into the gullet, f\ the aperture of the 

 glottis, g ; the tongue, h, with the right branch of the hyoid 

 bone at its base ; the median outline of the palate, ij k. The 

 passage from the posterior aperture of the nares, ij, opening 

 opposite the glottis, g, is seen extending obliquely upwards 

 and forwards, taking a somewhat winding direction, to the 

 nostril, /. In the upper part of this cavity, which is enlarged, 

 and recedes backward from the nostril, are three prominences : 

 one of a somewhat roundish form, m, hollow, membranous, 

 nearest the brain, and placed opposite the anterior part of the 

 orbit ; one of an elongated form, lying in the direction of the 

 nasal passage, formed of a somewhat cartilaginous plate, n, 

 once rolled upon itself, and by its upper edge attached to the 



