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NOTE ON THE LACEETILIAN SHOULDEE GIEDLE. 

 By E. Broom, M.D., D.Sc. 



(Eead June 27, 1906.) 



The shoulder girdle in the typical lizard is remarkable among 

 reptiles for the peculiar anterior development of the coracoid and 

 scapula. This anterior portion is for the most part cartilaginous and 

 fenestrated. The structure was carefully examined and figured by 

 Kitchen Parker in a number of lacertilian genera, and his views as 

 to the nature of the parts have been largely followed by later writers. 

 There are two large distinct bones which are pretty manifestly, in the 

 main at least, scapula and coracoid, but the question to be decided 

 is whether the cartilaginous anterior developments are to be regarded 

 as unossified portions of the scapula and coracoid or as precoracoid 

 or " epicoracoid." By Parker, and practically all writers since, the 

 inferior cartilaginous margin of the coracoid is called the epicoracoid, 

 and a portion of the anterior cartilaginous expansion the precora- 

 coid. In the present short paper I wish to suggest that neither of 

 these terms is justifiable, and that the shoulder girdle of the lizard 

 consists of simply a scapula, coracoid, and clavicle on each side and 

 an interclavicle between. 



Some confusion has arisen with regard to the names epicoracoid 

 and precoracoid. The former was, I believe, first applied to the 

 anterior coracoidal element in the Monotremes, the latter to the 

 anterior element in the Amphibians and primitive reptiles. It is 

 now, however, pretty generally agreed that the anterior element of 

 the Monotremes is homologous with the anterior cartilaginous bar in 

 the Amphibia and with the anterior of the two ventral elements of 

 the early reptiles, and therefore the same name ought to apply to 

 both. Though " Epicoracoid" is apparently the earlier of the two 

 names, only confusion would result from retaining it for the anterior 

 coracoidal element, since, following Kitchen Parker, it has been 



