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Show 312 PROF. HUXLEY ON THE ALKCTO ROMORPHAE. [May 14, Thp standing if I speak of them as the G A L L O - C O L U M B I N E series, t-uv best mark of the birds of this series is the sternum, which is almost always very readily recognizable, great as its variations are. I have endeavoured to show that the Pteroclomorphce completely connect the Pigeons and the Tetraonine division ot the Alectoromorphce. M. Blanchard has observed that " les Alectors, c est-a-dire les genres Crax, Urax, Penelope, ont des rapports etroits avec les Tetrao, en meme temps qu'ils indiquent l'affinite dont il a ete question entre les deux families des Gallides et des Columbides (I. c. p. 104). I confess I cannot perceive any close relation between the Peristero-podes and the Tetraonince. O n the contrary, the former appear to me to be more directly connected with the Gallinee, and especially with Numida. And though there are unmistakeable resemblances between the Peristeropodes and the Pigeons in the form of the feet and in that of the sternum, I am inclined to think, in view of the many differences of these birds, that they do not indicate any very close affinity. From the point of view of the Evolution theory, all the Gallo-columbine birds must be regarded as descendants of a single primitive stock ; and the relations of the different groups should be capable of representation by a genealogical tree, or phylum as Haeckel calls it in his remarkable ** Generelle Morphologie.' Such a phylum can only be put forward with confidence when a tolerably complete knowledge of the development and of the palaeontological history of a group has been obtained. But if, with our present information, I were called upon to draw out such a phylum of the Gallo-columbine birds, I should suggest some such scheme as the subjoined : - Peristeropodes Alectoropodes L J Pteroclomorphce Peristeromorphce I Tumici morphea Charadriomorph ce Ileteromorphee Tinamomorphce CARINATAE RATITAE i I Such a scheme implies that all the Gallo-columbine birds have had a common ancestry, and that the Pteroclomorphce are the nearest representatives in the direct line of that ancestrv This f |