68 PROFESSOR OWEN ON THE GENUS DINORNIS. 



DESCRIPTION OF THE PLATES. 



PLATE XXIII. 



Fig. L Upper view of the cranium of a large species of Dinornis (?). 



Fig. 2. Side view of ditto. 



Fig. 3. Under view of the premaxillary bone of the same cranium. 



PLATE XXIV. 



Fig. 1. Back view of the mutilated cranium of the young of the Dinornis giganteus {?). 



Fig. 2. Upper view of ditto. 



Fig. 3. Front view of ditto, from which the frontal bones have been separated at the 



coronal suture. 

 Fig. 4. Moiety of a vertically and longitudinally bisected cranium of a Palapteryx (?). 



a. Internal auditory foramina. 



V, Foramen for the nervus vagus and a vein. 



tr. Foramen for the third division of the trigeminal nerve. 



c, Cerebellar fossa. 



All these letters are in the epencephalic compartment of the cranium. 



0, Mesencephalic compartment lodging the optic lobes : and below these 

 the third ventricle and its hypophysis. 



p, The prosencephalic compartment. 



18, Olfactory chamber. 

 Fig. 5. Side view of the cranium of a Palapteryx (?). 

 Fig. 6. Base view of the cranium of another species of Palapteryx. 

 The letters and figures are explained in the text. 



