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breadth of the occiput, and the great breadth of the fore-part of the 

 frontal region, form the most peculiar features of the present cranium. 

 The occipital region above the foramen magnum is divided by three short 

 obtuse vertical processes into four depressions, the two median ones 

 being half the breadth of the two lateral, which are deeper than usual : 

 each depression is bounded above by a convex border, which does not 

 rise above the level of the calvarium to form a crest, but defines the occi- 

 pital from the coronal surface. 



A broad and deep depression separates the condyle on each side from 

 the ex-occipital process forming the posterior boundary of the tym- 

 panum : the broad basi-sphenoid descends vertically for a quarter of an 

 inch below, and at right angles with, the basi-occipital, separated from 

 the condyle by two small but deep depressions : this development of the 

 base of the skull is peculiar to the Dinornis among birds, and resembles 

 that in the Crocodile. The upper boundary of each temporal fossa is 

 well defined, but not elevated into a ridge ; a smooth and very slightly- 

 convex surface of the cranium, one inch ten lines in breadth, intervenes 

 between them ; a continuation of the same surface, four lines in breadth, 

 separates the temporal from the occipital fossae. A cellular air-diploe, from 

 two to six lines thick, divides the outer from the inner table of the cranium. 



The mutilated base of the present specimen exposes the upper border 

 of the pituitary depression, bounded anteriorly by the groove which 

 lodged the optic chiasma, and from which the optic foramina are con- 

 tinued outwards and forwards to the orbits. The outlets of the optic 

 foramina are separated by an interspace of one inch : the x\pteryx 

 amongst existing birds approaches nearest to the Dinornis in this pecu- 

 liarity ; but the Dodo most probably still more closely resembled the 

 Dinornis in the distinctness of, and distance between, the two optic fora- 

 mina. These foramina, in the present cranium of the Dinornis, are 

 smaller than those in the skull of the Ostrich, and indicate it to have had 

 a smaller eye, in which it must have resembled the Dodo. The olfactory 

 foramina are subcircular, three lines in diameter, separated by an inter- 

 space of two lines : the olfactory cavities extend backwards behind these 

 foramina noon the under surface of the cranium to within four lines of 



