SULA BASSANA. 



6-; 



Notes on Svla Bassana; CoMiMON Gannet. The following are additional notes on tlie anatomical 

 structure of the Common Gannet. 



The tongue is peculiar, being, in fact, one of the most singular tliat I have ever seen. It is short, about 

 •50 long, thick and flesny, rounded at the tip, slightly contracted in the middle, and bifid at the posterior 

 portion. Fig, 5, A, c. But the most noticeable feature is its elevated position, seen in a side view, at B c. 



The bone that supports it, tiie basi-h_val, is bent downward and tlic tongue is thus raised above the plane 



of the muscles about once its thickness. The whole strikingly resembles a moccasin-clad foot, having a bi- 



.fid heel. Other bones of the tongue are well developed, and the thyro-hyal. Fig. 5 A, li, h, are surroimded 



by powerful muscles. It is therefore probable that, although the tongue adheres below to the skin of the 



gula sac, it is retractable, and hence not quite functionless, as this organ must be in the Pelicans. 



The superior larynx is situated at some distance from the base of the tongue, 1.40, and the entrance 

 to the trachea, which is a slit .60 long. Fig. 5. A, q, is closed by strong muscles, s s. Within the entrance- 



D m C 



B 



C D 



Fig. 



Fig. G 



extending backward, is a tliin cartilaginous bone or septum, against which the lips of the muscles, that guard 

 the entrance, close; see Fig. ."i, 1), where is given a view of the tracheal orifice, q, open, and within it is 

 tlic septum, e, while at D is a side view of it base upward, the free end being widest. 



The whole structure is sujiported by a Y shaped bone which extends forward from the first tracheal 

 ring, Fig. 6, A, b, as seen from below: m being the first tracheal ring, and e, the lower side of the septum, 

 the intervening portion of the trachea being removed, while Fig. 7 b, shows a section across tiie lower jiur- 

 tion of the larynx, where it is about .7o wide, see Fig. 7, A, m, being tlie first tracheal ring, and c the low- 

 er side of the septum, the intervening portion of the trachea being removed: while at Fig. 7, A, is shown a 

 section across the lower portion of the larjmx, e, being the base of the Y-shaped bone. 



The trachea is flattened at the superior larynx, where it is about .7.j wide; sec Fig. 5, A, m, but as it 

 descends, it becomes gradually rounded and narrower, and is without dilation or special enlargement any- 

 where. It measures 11.50 to the inferior lar}^lx. 



