200 A POPULAR EXPOSITION OF THE 
{ Fig. 192.—Orthoceras Fig. 193 —O. bilineatum 
lateralis (Hall). (Hall). 
Fig. 195 —Trinucleus con: 
centricus (Haton). (Hall). 
Fig. 196.—Asaphus platycephalust (Stokes). 
+ Asaphus meyistos, from Cobourg, is a closely related species, but with the posterior 
angles of the head-shield prolonged into horns. See ante, Part IV. 
