334 CHARLES CLIFFORD MACKLIN 



The rounded upper border broadens dorso-laterally and bi- 

 furcates to enclose the hollow jugular recess (fig. 5), the ventral 

 limb passing laterally to become the ventral border of the pro- 

 cessus paracondyloideus (figs 2. and 4), while the dorsal is marked, 

 at its termination, by a small eminence, the anlage of the future 

 jugular tubercle (fig. 5). 



The hypoglossal canal, whose inlet and outlet have been noted, 

 pierces the condyloid portion in a direction from within out- 

 wards and forwards. It lies rather nearer the upper than the 

 lower border, between the jugular tubercle above and the ventral 

 foraminal prominence below. The right canal is unpartitioned, 

 but the left presents a bar of cartilage which separates its inner 

 third into cranio-ventral and caudo-dorsal inlets. This bar has 

 a general direction from above downwards, forwards and in- 

 wards (fig. 5). The outer two-thirds of this canal is not divided. 



When the sections are followed from behind forward it is noted 

 that two fasciculi of the hypoglossal nerve come into close ap- 

 position, one with the other (though they remain, for a time, 

 separated by their sheaths), just dorsal to the entrance of the 

 hypoglossal canal. These are of about equal size, and pierce the 

 dura as a single strand, to enter the canal (on the left side the 

 caudo-dorsal inlet) after a short sub-dural course. A third strand, 

 equal in size to the first two combined, may be seen to pierce the 

 dura shortly after the first two, but remains separated from the 

 latter (on the left side by the aforementioned septum) while 

 traversing the canal. Upon emerging the strands unite and 

 shortly after their exit they become intimately associated with 

 the vagus. In the canal they are accompanied by some small 

 veins — the anlage of the rete of the hypoglossal canal — and a 

 small artery. The great bulk of the canal space is, however, 

 filled with loose connective tissue. 



The processus paracondyloideus,^ already referred to more 

 than once, forms a conspicuous object as it springs from the 



1 It may be here noted that Voit uses the terra "processus paracondyloideus" 

 to apply only to the outer projecting tip (as it is found in the skull of the rabbit) 

 of the structure which I have designated by this term. Mead, in describing the 

 skull of the pig, uses the name "processus paroccipitalis" with the same meaning 



