Mr. A. R. Wallace on the Genus Pitta. 113 



Judging from external characters alone, it would seem almost 

 impossible to separate the Pittas from the Furmicariidce, or from 

 the above-mentioned genera with which Bonaparte associates 

 them. The first primary in all these groups is more or less de- 

 veloped — a character which at once distinguishes them from 

 the Turdidce, in which it is always rudimentary ; and the struc- 

 ture of the bill and feet, as well as the general form and habits, 

 present no constant differences of the slightest importance. 



An examination of the sternum and its appendages in these 

 birds does not throw much light on the matter, though it serves 

 to confirm the isolation of Pitta, which is expressed in its pecu- 

 liar colouring rather than in its external form or habits. In 

 Bi'achypteryx, Myiophonus, Zoothera, and Henicurus the general 

 form of the sternum is so much like that of the Thrushes, that it 

 is hardly possible to seize on any character to separate them. 

 In Myiophonus it has rather a lower keel, and the forked pro- 

 cesses of the episternum are rather blunter and more divergent, 

 while the coracoids are a little longer. Brachypteryx almost 

 exactly resembles Turdus fumidus in the form of the sternum ; 

 but the branches of the episternum are more slender. In Pitta 

 the differences are more apparent : the keel is high and arched, 

 and rises more abruptly from the extreme posterior margin than 

 in any of the above-mentioned species, and this margin is very 

 much narrowed. The anterior extremity of the keel is much 

 produced, and the anterior margin hollowed out in a deep curve 

 above the large epistermim. This is most remarkable on the 

 under surface, where it forms a perfect Y with slender cylin- 

 drical arms, differing in this part of the sternum from any 

 Passerine bird I possess. The coracoids are long and stout, 

 as in Myiophonus, considerably exceeding in length the sternum 

 itself from their insertion to the posterior margin. The only 

 Pormicariine sternum which I have been able to examine is that 

 of a species of Grallaria. This so closely approaches the same 

 part in Brachypteryx as to suggest a direct affinity; while the 

 differences, where they exist (as in the lower and less arched 

 keel), are such as to remove it rather further than that genus 

 from the form of the sternum in Pitta. 



It would seem therefore that, pending a more accurate exami- 



VOL. VI. I 



