170 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



nent " post-glenoid " process. The bone is stoutest at 

 this region, but becomes gradually lamelliform forwards, 

 and its anterior margin is furcate — the lower limb fitting 

 into the cavity of the dentary. The quadrate facet is 

 cartilaginous. The outer face of the articular is convex, 

 the inner concave. 



Angular (An.). — A small but perfectly distinct bone 

 situated at the postero-inferior angle of the articular. 



Meckel's Cartilage. — A long thin rod of cartilage 

 embedded in the articular behind, but lying quite freely 

 for the greater part of its length. It is situated near and 

 parallel to the ventral border of the inner or concave face 

 of the articular and projects slightly beyond the anterior 

 extremity of the ventral limb of the latter, the free end not 

 being ossified as a mentomeckelian as in Amia. The free 

 portion of Meckel's cartilage was 12mm. long in the speci- 

 men now described, and in a very large fish it attains a 

 diameter of about 2mm. 



Dentary (D.). — A thin bone, but well ossified at its 

 dorsal and ventral borders and strongly attached to the 

 dentary of the other side. It is strongly and almost 

 equally forked behind, and contains a large triangular 

 cavity for the reception of the lower limb of the articular. 

 Like the latter, its outer face is convex and the inner 

 concave. Quite near the symphysis it on this side and in 

 this specimen bore 3 teeth, opposite to which on the ven- 

 tral border a prominent process was set down. In a very 

 large specimen examined there were no teeth on this side, 

 their position being occupied by a roughened ridge. 



Maxilla (Mx.). — Takes no part in the gape. A stout 

 club-shaped bone, the expanded lower extremity of the 

 handle or shaft of which overlaps the lower jaw externally 

 at about the junction of the articular and dentary when 

 the mouth is closed. The shaft narrows down before ex- 



