BY PROFESSOR J. T. WILSON. 737 



Addendum, 



Since the above paper was read I have received through the courtesy of 

 Dr. J. F. van Bemmelen, a copy of his recently published contribution to 

 Semon's Zoologische Forschungsreisen in Australien, &c. , on the subject of 

 the Monotreme skull (der Schadelbau der Monotremen). The author deals 

 at some length with both adult, immature adult, and young conditions of the 

 snout skeleton, summarising and discussing the views of previous writers. 

 He adopts the designation of praevomer for the dumb-bell-shaped bone, and 

 defends the vomerine theory of its homology from certain recent criticisms 

 of Gegenbaur, which would seem to rest on a misconception. The paper is 

 a comprehensive one, and may be consulted in connection with the present 

 publication, although dealing with substantially older stages than those I 

 have been privileged to work with. 



