209 



more nearly allied to the " Galli " or to the " Hemipodii," because 

 these two groups either agree with each other or the characters 

 ditier too much within the " Galli " themselves. 



Vascular and Resinratory System. 



Ped'wiiomus possesses two caro tides profundte s. carotides sub- 

 vertebrales ; the left carotis is slightly weaker than the right and 

 covers the latter ventrally. Fediotiomus agrees in this respect with 

 most (but not with all) Rasores, not necessarily however because 

 of any close affinity with them, but because the presence of these 

 two subvertebral carotids is an old, unchanged feature, which per- 

 sists in most birds. In Tur^iix and in the Megapodid^e thei'e is 

 one carotis-conjuncta, but the right root, i.e. the basal portion of 

 the original right carotis, has been obliterated. It is not likely 

 that this condition has been developed directly from that of 

 Pediouomus, because in this bird the basal portion of the left 

 carotis is slightly the weaker one, on the contrary it shows that 

 Fedionomus has made an independent departure. The trachea is 

 peculiarly flattened dorso-ventrally, as in the Ratitte. Its numer- 

 ous cartilaginous rings are soft and very narrow. The Syrinx 

 exhibits no specially remarkable features, it agrees in its compo- 

 sition closely with that of Turnix and differs from that of the 

 Rasores. The pessulus is very weak and there is no distinctly 

 separated branchidesmus. The semi-rings of the bronchi surround 

 the whole ventral sui'face of the latter. The voice is produced (1) 

 by a pair of membranse tympaniformes interna^, which from the 

 pessulus onwards occupy the whole dorsal and median half of 

 each bronchus, (2) by several pairs of membranaj tympaniformes 

 externpe, the first of which is the largest and lies between the tirst 

 and second senu-ring of each bronchus, while smaller membranes 

 exist between two and two of the following semi-rings. The voice 

 is moderated by two pairs of muscles. Each m. sterno-trachealis 

 runs down from the larynx along the side of the trachea and is 

 inserted on to the lateral anterior process of the sternum. Each 

 m. tracheo-bronchialis begins at the point where the m. sterno- 

 trachealis leaves the tracliea, runs along its side and is inserted 

 upon the middle of the iirst bronchial semi-ring. The whole syrinx 

 is distinctly tracheo-bronchial. 



Alimeiitarij System. 



Neither Turnix nor Pedionomus possesses a crop, but the upper 

 half of the oesophagus is very dilatable. The gizzard is very strong 

 and of a rounded-off rhombic shape,* without the marked con- 

 striction on its upper anterior margin which exists in the gizzard 

 of Turnices and Rasores. Ihirnix and Pedionomus agree however 

 in having a slight indication of a pyloric stomach. The rest of 

 the alimentary canal of Pedionomus forms three great loops. The 



* Contents : quartz pebbles, and several hard Coloeoptera. 



