COLUMB^ 311 



In Goura there is no union posteriorly between succes- 

 sive tracheal rings, and the last two or three are quite dis- 

 continuous in the middle line posteriorly. 



In Didunculus also the last few tracheal rings do not 

 meet in the middle line posteriorly. 



As to the skull, the pigeons are schizognathous birds with 

 a slender vomer and basipterygoid processes, absent only in 

 Didus. They are also schizorhinal, but Goura, like Cursorius, 

 &c., among the Charadrii, is pseudo-holorhinal. The lacrymal 

 fuses below with the ectethmoid, and, indeed, forms with it 

 a nearly solid and often rather massive plate of bone. In 

 Goura, at any rate, the descending process of the lacrymal 

 is perforated in front by a largish foramen, as in the Bhea. 

 Some pigeons — ^e.g. LopholcBmus — have amedian small circular 

 foramen above the foramen magnum ; in Macropygia, &c., 

 this becomes a notch upon the upper border of the foramen 

 magnum. In Goura the foramen is totally absent. 



The skull of Didunculus is exceptional. The basiptery- 

 goid processes are very large. The palatines, instead of 

 widening out posteriorly, are narrow, solid bars throughout 

 their whole extent. Huxley states that the internal lamina 

 of these bones is ' altogether obsolete.' I find, however, in 

 my specimen a pair of small downwardly directed hooks 

 arising from where the palatines come into contact poste- 

 riorly, which I take to be the homologues of these structures. 

 Owing to the shortened and curved bill the bony nostrils are 

 much reduced in extent. There is no supraoccipital foramen. 

 There is, as in gallinaceous birds, a fusion between the post- 

 frontal process and the zygoma. 



There are 15 cervical vertebra in Goura, Garpophaga, &c., 

 14in Columha, Phaps, &c. Vertebrse 15-17 appear to be nearly 

 always ankylosed.^ The atlas is notched for the odontoid pro- 

 cess. The hypapophyses begin in Goura upon the eleventh 

 cervical and end upon the first dorsal. Four ribs reach the 

 sternum in Goura Victoria, of which the three first bear 

 uncinate processes. Ojily three reach the sternum in some 



' Fide Newton and Gadow {loc. cit. on p. 314). In Leucosarcia picata I 

 found four fused, and in Oeotrygon violacea only two. 



