195 



OBSERVATIONS ON THE DEVELOPMENT OF THE 

 MARSUPIAL SKULL. 



By R. Broom, M.D., D.Sc, C.M.Z.S., Corresponding Member. 



(Plates x.-xvii.) 



So far as I am aware, almost nothing has been published on 

 the development of the marsupial skull. In 1885, Kitchen 

 Parker published his magnificent monographs on the development 

 of the skull in the Edentata and Insectivora, and he informs us 

 that he had intended to follow these with accounts of the skulls 

 of the marsupials and monotremes; and we know, from various 

 references, that he had done much work on both groups. His 

 death, however, in 1890, interfered with his plans, and no one 

 else has ever taken up the work. 



Apart from the references in Parker's papers, almost the only 

 work that seems to have been done on the young marsupial skull 

 consists of various observations that have appeared ia papers 

 dealing with other points in the embryology. References to most 

 of these will be found in the list of literature. 



The present piece of work was commenced, and most of the 

 sections cut, twelve years ago, but it was found impossible to go 

 on with the research satisfactorily, as so little work had been 

 done on the very early stages of other groups of the higher 

 vertebrates. While ^Parker's work exhaustively treats of the 

 later development, his methods were not suited to the study of 

 the earliest stages. Our knowledge of the early development of 

 the skull of even the commonest mammals is still very imperfect, 

 and it is difficult to say whether some of the features of the 

 marsupial development are peculiar to the group or may be 

 common to other mammals. So far I have been able to examine 

 and compare the early chondrocrania in Eomo^ Ovis, Siis, Talpa. 



