1^97.] MB. F. E. BEDDABD ON INTEECENTEA IN BIRDS. 471 



TiNAMI. 



Among the Tinamous I have not seen free intercentra. 



Aic^, 



Among the Auks intercentra are quite as general as among their 

 near allies the Limicolae. 



In Uria troile there are no less than 6 free intercentra, which 

 lie well below the level of the centra and are but loosely attached, 

 so that they would be very readily detachable. There are two of 

 these bony nodules lying side by side between the ultimate and 



Fratercula arctica. Ventral aspect of caudal vertebra, showing free 



intercentra. 



penultimate free caudal. In Fratercula arctica (fig. 3) there are 6 

 very distinct and rather larger intercentra, which are not so loosely 

 attached as are those of Uria ; in F. corniculata I found only five. 



Pico-Passeees. 



In this extensive group of Birds free intercentra are infre- 

 quent and, when present, not numerous. There are, however, 

 frequently hypocentra, which may have the form of chevron-bones. 

 In Ti'iponacc feddeni, for example, the last four free caudals bear 

 double hypocentra, the free ends of which become fused in the 

 last two, thus forming chevrons. In Hylomanes gularis there is 

 one free intercentrum followed by two hypocentra. Dacelo gaudi- 

 chaudi has two free intercentra and five hypocentra. I could not 

 find intercentra in Coradas, UpujM, Megalcema, Halcyon, Merops, 

 Ehamphastos, Coitus. In Momotus lessoni there are two distinct 

 intercentra and two hypocentra. Among Hornbills, on the other 



