XT 



IY. 



The other elements must be determined by their relation to the preced- 

 ing, or to those parts from or in connection with which they originate. 



All those elements in immediate connection 1 with the pectoral fin and 

 the scapula must be homologous as a whole with the coraco-scapular 

 plate of the Batrachians, — that is, it is infinitely more probable that they 

 represent as a whole or as dismemberments therefrom the coraco-scapular 

 element than that they have independently originated. 



But the homogeneity of that coraco-scapular element forbids the identi- 

 fication of the several elements of the Fishes' shoulder girdle with regions 

 of the Batrachian's coraco-scapular plate. 



And it is equally impossible to identify the fishes' elements with those 

 of the higher reptiles or other vertebrates which have developed from the 

 Batrachians. The elements in the shoulder girdles of the distantly sep- 

 arated classes may be (to use the terms introduced by Dr. Lankester) ho- 

 moplastic, but they are not homogenetic. 



Therefore, they must be named accordingly. 



The element of the Dipnoan's shoulder girdle, continuous downwards 

 from the scapula, and to which the coracoid is closely applied, may be 

 named Ectocoracoid. 



V. 



Neither the scapula in Batrachians nor the cartilaginous extension 

 thereof, designated Suprascapula, is dissevered from the coracoid. 



Therefore, there is an d, priori improbability against the homology with 

 the scapula of any part having a distant or merely ligamentous connection 

 with the humerus-bearing element. 



Consequently, as an element better representing the scapula exists, the 

 element named scapula (by Owen, Giinther, etc.) cannot be the homologue 

 of the scapula of Batrachians. 



On the other hand, its more intimate relations with the skull and the 

 mode of development indicate that it is rather an element originating 

 and developed in more intimate connection with the skull. 



It may therefore be considered, with Parker, as a Posttemporal. 



VI. 



The shoulder girdle in the Dipnoi is connected by an azygous differen- 

 tiated cartilage, swollen backwards. 



It is more probable that this is the homologue of the Sternum of Ba- 

 trachians, and that in the latter, that element has been still more differen- 

 tiated and specialized than that it should have originated de novo from 

 an independently developed nucleus. 



1 The so scapula and suprascapula of most authors are excluded from this connec- 

 tion. 



