30 
Plate IV 
Figure 1. Tetragonosaurus cranibrevis. Type No. 8633, Geol. Surv., Canada. 
Skull and jaw. ^ natural size. (Negative No. 76987.) 
Figure 2. Lambeosaurus clavinitialis. Type No. 8703, Geol. Surv., Canada. Skull 
and jaws. ^ natural size. (Negative No. 77487.) 
