115 
The right Bulbus olfactoriust lies mostly under the 
corpus striatum (the latter is the cerebral hemisphere of 
older authors). Behind, it is free, unconnected with the 
striatum and ends bluntly, but in front it acquires a firm 
connection with the striatum. Anterior to this again it 
separates once more from the striatum. So far it has been 
increasing in size, but it now begins to taper down, its 
ventral portion becomes fibrous, and its dorsal divided 
into two. The upper or cerebral portion disappears in 
front, and the remainder narrows down into the cylindrical 
nervus olfactorius. Both olfactory nerves lie to the right 
of the upper or left optic nerve. As the nerve passes 
forwards it becomes divided by connective tissue strands 
into two or more fasciculi, each of these again being 
further subdivided into small bundles of fibres. The 
right olfactory passes through the foramen olfactorium in 
the right prefrontal, turns up at once and breaks up in 
the olfactory lamine of the right nasal chamber. 
The left Bulbus olfactorius is not free behind like the 
right, but passes imperceptibly into its striatum. Nor is 
it situated below the latter, but between the two striata 
(see fig. 28). The appearance therefore of this portion of 
the brain is very asymmetrical, and suggests a rotation 
towards the right side of the ventral axis of the brain 
only. The left bulbus is perceptibly smaller than the 
right, but the left striatum extends further forwards than 
its fellow. The bulbus separates from the striatum in 
front, becomes fibrous at its right ventral corner and gives 
off the left olfactory. nerve, which passes at once to the 
right side, so as to lie near the right bulbus. The left 
+ This structure is also called by some authors the Tuberculum 
olfactoriwm (Stannius) and Lobus olfactorius. We have no space to discuss 
the precise significance of each of these three terms, if indeed they have 
any (but see Elliot Smith, Jour. Anat. and Phys., xxxv., 1901). 
