Fig. 493. — Mesozoic cephalopods : A, Tropites subbullatus (Triassic), side and front 

 views ; B, Development of sutures in Tropites ; C, Lytoceras fimbriatum (Jurassic) ; 

 D, Perisphinctes achilles (Jurassic) ; E, F, Meekoceras gracilitatis (Lower Triassic), 

 front and side views ; G, Sagenites herbichi (Upper Triassic) ; H, Turrilites catenatus 

 (Cretaceous) ; /, Ceratites nodosus (Triassic) ; /, Baculites, showing the complexity of 

 the sutures (one segment is shaded to emphasize this) ; K, Cardioceras cordatum (Juras- 

 sic), side and front views ; L, Scaphites nodosus (Cretaceous). 



