TINAMI 



493 



femorocaudal muscle is a striking resemblance to the Stru- 

 thioaes ; the peculiar accessory biceps muscle of the arm 

 may have its degenerate counterpart in a sheet of strong 

 tendinous tissue which runs along the humerus in certain 

 ratites. 



The following table shows some of the more striking 

 likenesses of the Tinami to the Struthiones and Galli : — 



STRUTHIONES 



Definition. — Pliglitless birds without stiff oontour feathers. Oil gland 

 absent. "Wing small. Expansor secundariorum and biceps slip 

 absent. Semitendinosus and its accessory always present. An 

 additional slip to accessory femorocaudal present. Skull 

 dromeeognathous with basipterygoid processes ; holorhinal. 

 Sternum without a well-developed carina. Coraco-soapular 

 angle wide. Coracoid fused with scapula. Caeca large. 



As will be seen from the above definition, the characters 

 of this group are to a considerable extent negative characters. 

 They are for the most part such characters as are correlated 

 with the loss of the power of flight. We need not, therefore, 

 lay too much stress upon them as indicative of the natural- 

 ness of the group. But even when these characters (as, for 

 instance, the absence of the carina sterni, the open angle 

 between the coracoid and scapula, the absence of a plough- 

 share bone, which, moreover, is occasionally and exception- 

 ally present. There is a skeleton of an old Struthio in the 

 Cambridge Museum in which several of the last vertebrae 



