OSTEOLOGY 



furcula is connected with a ligament (e.g. Psophia) by articu- 

 lation (e.g. Herodiones) or by direct synostosis with the carina 

 sterni. In the gallinaceous birds the furcula does not come 

 into near relations with the carina, and in Opisthocomus 

 quite exceptionally the bone is ankylosed with the spina 

 sterni on the one hand, and with the coracoids, so firmly 

 that ' no trace of the primitive distinctness of the bones is 

 discernible.' There are also considerable variations in the 

 degree of the connection between the furcula and the coracoid 

 and scapula. 



In a few birds the ends of the clavicles where they arti- 

 culate, or at least are connected, with the coracoid and scapula 

 have a process, the acrocoracoid process of the clavicle. This 

 is seen, for instance, in the Anseres, and the rudiment of such 

 a process in the flamingo appears at first sight to be a duck- 

 like character in that bird. But the same process is also 

 developed, and to a great extent, in the Alcedmidae, a fact 

 which must be borne in mind before coming to any such 

 conclusions. 



FURBRINGER has devoted some space to describing and 

 illustrating the relations at their articulations between the 

 clavicle, coracoid, and acrocoracoid. The two extremes may 

 be seen in Phahicrocorax and Psophia ; in the former the 

 clavicle articulates with the acrocoracoid only, and does not 

 reach the scapula ; in the latter, where the procoracoid is 

 well developed, the clavicle comes into contact with all 

 three. 1 Further details will be found under the description 

 of the different groups. 



The Fore Limb. The fore limb is present in all birds except 

 most Dinornithidae, where up to the present no trace of one 

 has been discovered. In Hesperornis only the humerus 

 appears to exist ; in Apteryx, Dromaus, and Casuarius there 

 is but one finger. With these exceptions the wing of birds 

 consists of a humerus, radius and ulna, carpus, metacarpals, 

 and three fingers (with sometimes a rudiment of a fourth) ; 

 even Archaopteryx has not been definitely shown to possess 



1 A. TSCHAX, Recherchcs sur VExtr&mitf AnUrienre dcs Oiseaux et des 

 Reptiles, Diss. Inaug., Geneva, 1889. 



