BA UR. 



[VOL. I. 



The increase of the number of cervical vertebrae in the Plesio- 

 sauria is certainly not produced by a shifting backwards of the 

 shoulder girdle, but by addition of new vertebrae by intercala- 

 tions, as will be seen from the following table : 



TABLE SHOWING THE NUMBER OF VERTEBRAE IN PLESIOSAURIA. 



Everybody who will examine this table must admit that the 

 increase of the number of cervical vertebrae can only be 

 explained by intercalation. We see, therefore, that intercalation 

 really occurs. 



All the cases enumerated in the table of the Amphibia 

 caudata and the cases of the Crocodilia demonstrate the shift- 

 ing of the pelvis, a process which I have always admitted. 



In the Ecaudata (Batrachia) we find the same processes, as 

 has been shown in an excellent paper just published (after I 

 had written my paper) by W. G. Ridewood, " On the Devel- 

 opment of the Vertebral Column in Pipa and Xenopus," Anat. 

 Am., xiii, Bd. 10, April 1897, No. 13, pp. 359~37 6 > with 4 



figures. 



* 4- means that the tail is not completely preserved. 



