STRUCTURE AND CLASSIFICATION OF BIRDS 



Europe, especially the latter, as it has some claims to repre- 

 sent the most ancient form of cuckoo, with complete muscle 

 formula and tracheo-bronchial syrinx. 1 



MUSOPHAGI 



Definition. Oil gland tufted. Aftershaffc present. Quintocubital. 

 Rectrices, ten. Muscle formula of leg, ABXY + . Expansor 

 seoundariorum present. Biceps slip absent. Caeca absent. Both 

 carotids present. Skull holorhinal, desmognathous, without 

 basipterygoid processes. 



This group of birds, purely African in range,' 2 is divisible 

 into three genera, Corythaix, Musophaga, and Scliizorhis. 

 These genera do not show a large amount of structural 

 variation. 



As to the pterylosis, the two ventral tracts are double 

 upon the neck (in C. albocristata) ; they remain separate 

 until just in front of the cloaca, being especially weak and 

 narrow in the breast region. Longitudinally arranged rows 

 of feathers connect the pectoral tracts above with the 

 humeral. The other important external characters are stated 

 in the definition. 



In Schizorhis the normal arrangement of the leg arteries 

 obtains. 



In Corytliaix and Musophaga the femoral artery is the 

 -one developed. The right jugular is the largest, and in 

 Corythaix albocristata, seems to have entirely disappeared. 



In the liver the right lobe is the larger, 3 sometimes 

 considerably so. The gall bladder is present, and sometimes 

 is elongated in form. The tongue is short and triangular ; 

 the proventriculus is zonary, the gizzard weak. The in- 

 testines are capacious and short, without ca3ca. The following 

 are a few measurements : 



1 Cf. also partial persistence of basipterygoid processes in Phoenicophainse. 

 ; The extinct Necrornis of French Miocene may be a Touraco. 

 3 The viscera are described by OWEN for Corythai.i- /><>i-j>Jii/rcoIo}i]iit, I'. Z. ,S' 

 1834, p. 3, and by MARTIN for Corythaix Hiitfnnii. ibid. is:-{li, p. 3'2. 



