[Pboc. Rov. Sue. Victoria, 25 (N.S.), I't. I., 1012.] 



Art. XT. — .-1 Studi/ of the Prognat/tisiii of tlw. TaaiiuLiilan 



Aboriginal. 



By L. W. G. BUCHNER 



(Government Research Scliolai- in the Anatomy Department of the Univer.sity 



of Melbourne). 



[Read 11th July, ]!)12.] 



According to T'opinard (1), prognathism has, since the time of 

 Prichard, been understood to mean '' the elongation and prominence 

 or the obliquity of the jaws, cominion in the black races of Africa and 

 Oceania, accidental in some Europeans." As thus defined, Topiuard 

 lias divided prognathism into two categories. (1) ^superior facial, and 

 (•J) inferior facial. 



Tiie former he still further subdivides into three divisions: — 



(a) The entire facial prognathism. 



(b) The superior facial prognathism. 



(c) The alveolo subnasal prognathism. 

 The latter he divides into two : — 



(a) The inferior dental prognathism, 



(b) The inferior maxillary region, the teeth being indepen- 



dent of the jaws. 



In reviewing the various methods of determining that form of facial 

 projection already defined as '' superior facial," Topinard gives a brief 

 resume of ten methods, which include such well-known angles as Cam- 

 pers facial angle, Welcker's nasobasal angle. Yogi's angle (a modifi- 

 cation of Welcker's angle), Vogt's palatine and vomerian angle, and 

 Virchow's method, the old German method, that is, the comparison of 

 the glabella-occipital line with the alveolo-occipital line ; Busk's facial 

 radii, Broca's auricular radii, the same author's projection method, 

 Jjucae's method, and, finally, Topinard describes his own method, by 

 means of which he estimates the " true '" prognathism, determined by 

 means of the angle formed by the profile line with the horizontal 

 plane. 



Ihering (2) and Lissauer ('}) likewise give a resume of the methods 

 employed by the German scho'ol up to 1872. 



With the possible exception of Topinard's method, most of the 

 above are now out of date. The more modern means of determining 

 prognathism and dolichocephaly will be discussed later. 



Of the factors which produce prognathism, many investigations 

 have been made ; for example. Duckworth (4) points out that prog- 

 nathism is dependent (»n two factors, firstly, the size of the teeth and 



