THE SKELETON 39 



Together with the pro-coracoid region = 



Sternum ........ Funk (1827). 



Coracoide ........ Perrin (1899). 



This is by far the largest portion of the pectoral girdle and extends 

 mesially from the glenoid cavity across about two-thirds the width 

 of the body, so that there is an overlapping of the right and left sides. 

 It is apparently immaterial in Salamandra maculosa whether the 

 right is ventral to the left or vice versa, since both arrangements are 

 found to occur with about equal frequency, although in Triton and 

 S. atra the former appears to be the more frequent condition. In 

 maculosa the controlling factor is probably mechanical pressure 

 during intra-uterine life.' The coracoid portion forms a more or less 

 semicircular plate, deeply hollowed, with its convex surface ventral. 

 Only a very small portion, in the region of the glenoid cavity, is 

 ossified. The remainder is cartilaginous. Like the pro-coracoid its 

 free edges are exceedingly thin, while the postero-mesial edges are 

 attached by connective tissue to the sternal plate (q.v.). It also forms 

 a faceted lip to the posterior border of the glenoid cavity which is 

 entirely cartilaginous but is not so pronounced as that formed by the 

 pro-coracoid. The overlapping portions of the coracoids lie im- 

 mediately ventral to the heart, which they protect. 



Parker designates as 'epicoracoid' the antero-mesial portion which 

 projects slightly from the general contour, while Sabatier applies the 

 same term to the whole cartilaginous portion. Engler, however, 

 shows quite clearly that a true epicoracoid is absent from Urodeles.^ 

 It should be noticed in this connexion that the overlapping of the 

 coracoids — known as arcifery — is not identical with the Anuran 

 arcifery (e.g. Bufo), since in these animals it is the epi-coracoids which 

 overlap and not the coracoids. 



{d) The Sternum (most authors) (Fig. 22). 



Cartilaginula quadrata intermedia .... Funk (1827). 



The sternum of the Salamander is a small median cartilaginous 

 plate, lying behind the coracoids. Its shape is roughly that of an 

 equilateral triangle with the apex directed forwards, and a short pro- 

 jection from the middle of the base pointing posteriorly. The sides 

 are grooved to receive the postero-mesial edges of the coracoid 

 cartilages. These grooves are fairly deep and do not merge into one 

 another anteriorly, but are divided by a septum, so that one groove 



1 Cf. Engler (1929). 



2 Except in Siren lacertina and Cryptobranchiis allegkaniensis. 



