in the Mandibular Arch of Chimsera monstrosa. Ill 



shows the body of the narrow tail-like portion and the 

 termination of the dorsal plate (fig - . 3 b). 



Fi°r. 2. 



ab.b. 



Abnormal bone, first case. 



a, triangular anterior portion ; b, tail-like posterior portion ; 

 d.pl., dorsal plate • Ug., ligament. 



Fie:. 4. 



Fit 



1 



ab.b. 



Fig. 3. — Sections, (a) through the triangular anterior portion, (b) through 

 the tail-like posterior portion. Marked a and b respectively 

 in tig. 2. 



Fig. 4. — Abnormal bone, second case, ao.b., abnormal bone; liff., liga- 

 ment. 



In the second specimen the bone consists of a thin plate- 

 like structure, having the appearance, when looked at from 



