DICHOTOMY. 105 
nished with an aftershaft exactly resembling, in its 
relation to the main hair-shaft, that figured in fig. B. 
In the case of teeth it is not unusual in man to 
See RN 
S = SSgEkg]?2{E{}.2& [SSN 
SS SSS SQ Ss 
eee ZIG LE 
N 
Fic. 52.—A, feather and aftershaft of the Himalayan 
Monaul (Lophophorus impeyanus) ; B, feather and 
aftershaft of the Emu (Dromeus nove-hollandie). 
find a double incisor or bicuspid tooth. In such cases 
the fangs and crowns are usually firmly united together, 
but the line of union is indicated by a deep, well-pro- 
nounced furrow. Such a condition of the teeth is 
