Tasmanian Crania. 125 



Z =Zentiinn. 



BGL = Upper Glabella Angle. 

 LGBa = Lower Glabella Angle. 

 BGBa = Anterior Glabella Angle. 



On making further experiments Kbiatseli was struek with the con- 

 stant rebitionslii]> which the jioint K bore to the basion In-egma line, 

 the point being always in that line, or a few millimetres to one or 

 other side of it. On adding the glabella lambda line, Klaatsch 

 noticed that it almost always intersected the basion bregma line at a 

 right angle. The point of intersection he therefore terms tlie 

 '■ Zentrum." 



On account, therefore, of, tirstly, the centre of gravity falling in, 

 or close to, the basion bregma line ; secondly, that line intersecting the 

 glabella lambda line at a right-angled " Zentrum," and, lastly, the 

 natural coincidence of this glabella lambda plane with the natural 

 position of the head in life, Klaatsch proposes that this plane should 

 be made the natural base line for all future cranionietrical work. 

 Upon this base line he further proposes that a quadrilateral figure 

 should be devised, the sides of which are drawn from the glabella to 

 the bregma, the bregma to the lambda, the lambda to the basion, and 

 the basion to the glabella, respectively. These four lines, therefore, 

 correspond in part, but not entirely, to the chords of the frontal, 

 parietal and occipital bones, and the " basi-cranial " axis. On the four 

 sides of this quadrilateral figure Klaatsch further proposes the erec- 

 tion of a series of triangles for the study of angles of curvature and 

 other allied points in connection with the several bones of the skull. 



The whole of this system he designates as a " craniotrigonometrical " 

 method for studying the skull (Fig. 2). One advantage, amongst 

 others claimed ))v its author for his method, is that the various angles 

 will now receive their correct nomenclature, as Klaatsch, in common 

 with others, has criticised Schwalbe's method of naming or misnaming 

 these angles. Klaatsch. for example, proposes to obviate any con- 

 fusion that may arise by designating angles by the position of their 

 apices. He says : '■ Mein Prinzip ist jeden Winkel nach seinem 

 Scheitelpunkte zu beneunen.' He thus terms the angle l)ounde(i 

 by the bregma glabella and laml)d:i glabella lines the upper glabellar 

 angle. (See Fig. 2.) 



