625 



Jenny. H., Anatomischer Anzeiger 1912. 



Kemmetmüller, H., Über eine seltene Varietät der Art. vertebralis. Anatomische 



Hefte 1911. 

 MfiRiEL et Florence, Anomalies de l'artere au point de vue operatoire. Bull. 



et Mem. Soc. anat. Paris. Annee 78. 

 Morestin, Anomalie de l'artere linguale. Bullet, de la Societe anat. de Paris. 



Annee 69, 1894. 

 ZüCKERKANDL, Über ein abnormes Verhalten der Zungenschlagader. Wiener 

 medizinische "Wochenschrift 1881. 



Nachdruck verboten. 



The Morphology of the Coracoid. 



By R. Broom, D. Sc, C.M.Z.S. 

 With 16 Figures. 



On passing from the higher mammals to the Monotremes, the 

 Birds, Reptiles, and Amphibians we encounter a serious difficulty in 

 tracing the homologous of the coracoid. In the monotremes we find 

 two ventral elements in the shoulder girdle. In modern reptiles and 

 in birds we find but a single coracoid, but in most Permian reptiles 

 there are again two ventral elements. And the questions which have 

 to be settled are these- — when two elements are present are the two 

 together homologous with the human coracoid ossification or is only 

 one, and if one which is the true coracoid, and further when only 

 one element is present as in modern reptiles and birds is it homolo- 

 gous with the singer element found in higher mammals. 



Until KiTcmN Parker in 1864 and more fully in 1868 took up 

 the study of the structure and development of the vertebrate shoulder 

 girdle the problem can hardly be said to have been seriously tackled. 

 Parker's beautiful work to a large extent brought order out of con- 

 fusion. Unfortunately he only studied living forms. He regarded the 

 single coracoidal element of reptiles and birds as homologous with the 

 coracoid of higher mammals. The anterior element in the monotremes 

 he does not regard as homologous with the amphibian precoracoid 

 and evidently regards it as a neomorph homologous with the anterior 

 cartilaginous part of the lacertilian coracoid. 



In 1887 and 1893 Howes published two papers in which he dis- 

 cussed at length the coracoid homologies. He endeavoured to show 

 that the mammalian coracoid process is made up of two elements, one 



Anat. Anz. Bd. 41. Aufsätze. 40 



