500 Mr. G. L. Bates on the 



specimen the vinculum was either absent or so slight that 

 it was easily broken. This case seems to show that the cha- 

 racter of the vinculum is somewhat variable. But there is no 

 doubt about its presence in the other specimens examined. 



According to Gadow;, this vinculum is found_, among 

 Passeriformes, only in the Eurylsemidse. 



Sternwn. — While I think that a comparison of thoroughly- 

 cleaned sterna of Smithornis with those of other genera of 

 Passeres would show interesting though slight differences, 

 only one point can be stated now, and it is a point of simi- 

 larity and not of difference. The spina sternalis is deeply 

 forked or Y-shaped, as in most Passeriformes. Gadow^s 

 statement regarding the Eurylsemidse is " Spina externa long 

 but simple, with rounded tip or scarcely indicated fork.^' 



Tongue. — The tongue in Smithornis is not only broad, to 

 suit the shape of the bill, but markedly thick and fleshy, 

 though with thin edges. In this fleshy tongue is perhaps to 

 be found the clue to the mystery of the way in which the 

 bird's peculiar noise is produced. 



A character found in one of the little bones of the hyoid 

 apparatus in Passerine birds, though I have never seen a 

 reference to it in any book, can be given here with some 

 confidence as being important because constant. It has 

 been my custom for a good while to pull out (when it was 

 not too much trouble) the tongues of birds skinned, and to 

 remove as much of the muscle on the hyoid bones as could 

 be quickly done, and dry and label these tongues with the 

 bones attached. Thus quite a collection of birds' tongues 

 has been formed. A comparison of these shows that the 

 little urohyal bone, situated between the bases of the hyoid 

 horns and lying with point downwards, when in position in 

 the bird, against the front of the thyroid cartilage, has a 

 peculiar shape in all normal Passeres. In these the free 

 end of the urohyal is very flat with a thin border of car- 

 tilage at the edges and tip. The amount of this flattening 

 ftnd widening varies among the families of Passeres, but 

 there is similarity in this regard between members of each 

 family. The Pycnonotidae have the urohyal the widest 

 and flattest of any of the birds I have observed, and the 



