CURVE OF SPEE IN MAMMALS 
165 
This method of Spec is open, however, to some criticism and, be- 
ginning with human material, I have employed the following pro- 
jection method which seems to be better adapted for the purpose. 
Fig. 1. Diagram Showing the Plane of Projection and also the Form op 
Callipers used for the Measurements 
OP, projection plane used by Spee; PQ, projection plane used by the author; a, b, c 
. . . . and i, each buccal cusp from the first bicuspid to the third molar; K, middle 
point of the condyle. 
The plane, on which the cusps are to be projected, has been so 
selected that it is perpendicular to the horizontal plane (on which 
the lower jaw^ rests), and parallel to the line PQ — figure 1 — which 
connects the buccal cusp of the first bicuspid and the disto-buccal 
' For the preliminary examination of the curve of Spee, I used exclusively the lower jaw, 
because it is easier to manipulate in applying my method. 
