til PROCEEDINGS OF THE ANATOMICAL AND ANTHROPOLOGICAL 



undoubtedly one of the most important recent works on the subject 

 and seems to me to merit greater consideration. 



Professor E. Fawcett (5) in 1904, in the Proceedings <\f f/tc 

 . I luitomical Society of Great Britain and Ireland, states that Meckel's 

 cartilage ossifies from the mental foramen to the middle line, but that 

 the dentary ossification covers it in front. He describes a cartila- 

 ginous mass in the condyle and is doubtful if any splenial centre 

 exists, and says that probably the whole membranous jaw arises 

 from one centre. 



Professor Karl von Bardeleben (t) in February, 1905, in the 

 Ainituniixrln'r Anzeiger, argues that the chin in man and mammals is 

 a special skeletal element the os mentale and that there are also 

 found in the lower jaw, condyloid, coronoid, angular, marginal and 

 dentale as separate elements. His views are based largely on the 

 macroscopic appearances presented by young and adult jaws. The 

 only foetal jaws he has examined are human in the later months of 

 foetal life for the rest he accepts the researches of previous workers. 



At a meeting of the Anatomical Society of Great Britain and 

 Ireland in May of this year (9) I gave a demonstration on the de- 

 velopment of the lower jaw in man, and showed by slides and speci- 

 mens that the human lower jaw is developed in membrane as a single 

 skeletal element ; that in connection with the condyle and coronoid 

 process cartilaginous pieces are developed, but that these do not 

 indicate separate elements ; and that Meckel's cartilage towards its 

 anterior extremity becomes ossified and helps to form the lower jaw 

 in the region of the incisor teeth. 



The present paper is a detailed account of the research on which 

 my former paper was based. 



PRESENT RESEARCH. 



The quite different and opposing views expressed regarding the 

 Ossification of the lower jaw seem to me to arise largely from im- 

 perfect methods of research. One cannot form a correct picture of 

 the process by selecting a developing jaw here and there from different 



