OF THE NUBIAN GIRAFFE. 231 
the muzzle to the vent, the length of the spinal chord from the corpora pyramidalia to 
the commencement of the swelling, giving off the brachial plewus, was three feet three 
inches. 
The origin of the cervical nerves from this part of the chord presented an uncommon 
appearance ; for, the elongation of this part during foetal development, having pro- 
ceeded by means of uniform interstitial deposition, the roots of the nerves had be- 
come equally separated from each other ; and as the lowest filament of the root of one 
nerve was not further removed from the highest of the next below, than this from the 
succeeding filament of the same nerve, the filaments composing the root of a single 
cervical nerve extended over a considerable space: thus the third cervical nerve 
derived its filaments from a tract of the spinal chord measuring fully six inches. The 
inferior roots on leaving the medulla ascend and the superior ones descend to the per- 
foration in the dura mater at a very acute angle with the spinal chord, and they may be 
traced for a short distance in a direction corresponding with their course externally, the 
upper filaments upwards, or towards the brain, the lower ones downwards, within the 
substance of the spinal chord. In the posterior roots of the cervical nerves, one and ; 
sometimes two of the lowermost filaments of one nerve are continued uninterruptedly 
into the uppermost filaments of the succeeding nerve of the same side. These com- 
municating chords are of conspicuous size, and lie rather loosely in the subarach- 
noid tissue, on the surface of the spinal chord: there appear to be in some places 
very minute nervous filaments passing from the substance of the chord to the anasto- 
motic loop. In one place I traced a corresponding superficial connecting loop between 
the anterior or motor roots of contiguous nerves. (Pl. XLIII. fig. 2.) 
The brachial plexus is formed principally by the first two dorsal nerves ; from these 
to the large nerves forming the lumber plecus there intervene seventeen pairs of nerves ; 
the four following nerves, or those of the eighteenth to the twenty-first pair inclusive, 
are principally enlarged to form the plexus supplying the hinder extremities.’ 
From the remarkable length of the neck of the Giraffe the condition of the recurrent 
nerves became naturally a subject of interest: these nerves are readily distinguishable . 
at the superior third of the trachea, but when sought for at their origin it is not easy 
to detect them or to obtain satisfactory proof of their existence. Each nerve is not due, 
as in the short-necked Mammalia, to a single branch given off from the nervus vagus, 
which winds round the great vessels, and is continued of uniform diameter throughout 
their recurrent course, but it is formed by the reunion of several small filaments derived 
from the nervus vagus at different parts of its course. The following is the result of a 
' In the male Giraffe which died at the Society’s Gardens, the lameness and subsequent paralysis of the 
hinder extremities were caused by an ezostosis from the inner surface of the superior arch of the last lumbar 
vertebra, which pressed upon the posterior enlargement of the spinal chord, and had occasioned inflammation 
and thickening of the dura mater. The exostosis was a consequence of a wound of the spine received when 
the animal was captured. 
2H2 
