78 



ON THE MENTAL QUALITIES AND 



cases to examine the brain itself, it is obviously of great 

 importance, that the size, configuration, and relative pro- 

 portion of that organ, can be detected by an inspection of 

 the cranium alone. Phrenologists, accordingly, have la- 

 boured to prove that such is the case, with what success we 

 shall presently see. 



On making a section of the cranium of a bird, several 

 distinct cavities are seen on its internal surface. The largest 

 and most important of these is that for lodging the cere- 

 brum, or brain proper, and is divided in the mesial line by 

 a slight bony elevation, defining the boundaries of each 

 hemisphere. There are, besides, lower down and slightly 

 posterior, two cavities of smaller size, for the reception of 

 the optic lobes ; and beneath them is situated a well marked 

 cavity, in which is contained the cerebellum. Besides these 

 principal cavities, of which that for lodging the cerebrum 

 is by far the largest, there are two others of smaller size at 

 the base of the skull, the one for the reception of the me- 

 dulla oblongata, the other, analogous to the sella turcica, 

 in man, for containing the pineal gland. These depres- 

 sions are more obvious in some classes of birds than in 

 others. Thus, in two sectioned skulls of the hen-harrier, 

 ( a bird of prey), lying before me, the boundaries of each of 

 the cavities I have just mentioned are much more distinct 

 than in the skulls of two magpies similarly treated. In the 

 latter, for example, there is scarcely any boundary between 

 the cavity for the cerebrum and those for the optic lobes, 

 far less is there the projecting bony ridge to be seen in the 

 crania of rapacious birds in general. 



On the external surface of the cranium of birds, we see 

 none of those small elevations and depressions so frequent 



