YELLOW-THROATED VIREO. 



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smaller end being rather rounded, and is marked with a few scattered 

 spots of a deep brownish-crimson, on a beautiful flesh-coloured ground. 

 The Vireos are intermediate between the Flycatchers and the Shrikes, 

 but in the structure of their digestive organs, and in the arrangement 

 of the muscles of the trachea, more allied to the latter. In a male pre- 

 served in spirits, the roof of the mouth is slightly concave, with two 

 palatal ridges, and an anterior median ridge ; the posterior aperture of 

 the nares is linear-oblong, 5 twelfths in length, its margins papillate. 

 The tongue is rather short, 4^ twelfths long, narrow, triangular, very 

 thin, emarginate and papillate at the base, flat above, tapering, to a 

 horny, deeply slit, lacerated point. The width of the mouth is 4i 

 twelfths. The oesophagus is 1 inch 9 twelfths long, funnel-shaped at 

 the commencement, at the distance of half an inch, 

 its width is If twelfth, and thus continues until 

 it enters the thorax, soon after which it enlarges to 

 form the proventriculus, of which the breadth is 3 

 twelfths. The stomach is of moderate size, of a 

 broadly elliptical form, considerably compressed ; 

 its length 6 twelfths, its breadth 5 twelfths, its mus- 

 cles pretty large and distinct, its tendons of mo- 

 derate size ; the epithelium thin, reddish-brown, 

 with eight longitudinal rugae on one side, and five 

 on the other. The belt of proventricular glandules 

 is 2\ twelfths broad. The intestine is 5| inches 

 long, from 1^ twelfth to 1 twelfth in width, the 

 rectum 2 twelfths at first, the cloaca globular, 

 about 4 twelfths ; the coeca \\ twelfth long, about 9^ 

 \ twelfth wide, and placed at the distance of 9 

 twelfths from the extremity. 



The trachea is 1 inch 2 twelfths long, from 1 

 twelfth to I twelfth in width, moderately flattened, 

 its rings rather firm, about 50, with 2 dimidiate ; the muscles disposed 

 as in the Thrushes and Warblers, there being four pairs of inferior 

 laryngeal on each side, besides the sterno-tracheal. The bronchi short, 

 slender, of about 10 half rings. 



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