152 Zoological Society. 



elongation of this part of the spinal chord ; the space between the 

 lower filaments forming the root of one nerve, and the upper filaments 

 of the root of the succeeding nerve was not more than the space be- 

 tween the individual filaments of each root ; whence it would seem 

 that the elongation of the cervical portion of the chord was produced 

 by a general and uniform interstitial deposition during foetal develope- 

 ment, which thus eflfected an equable separation of these filaments ; 

 so that a single nerve, as in the case of the third cervical, might derive 

 its origin from a space extending six inches in length. 



In the dissection of the abdominal muscles no peculiarity of im- 

 portance was noticed ; but in the neck there existed a highly inter- 

 esting modification of the parts which effect the retraction of the os 

 hyoides. The pair of muscles which, as in some other Ruminants, 

 combines the offices of sterno-thyroideus and sterno-hyoideus, arose 

 in the Giraffe by a single long and slender carneous portion from the 

 anterior extremity of the sternum ; this fleshy origin was nine inches 

 long, and it terminated in a single round tendon six inches in length ; 

 the tendon then divided into the two muscles, each division beco- 

 ming fleshy, and so continuing for about 1 6 or 1 8 inches ; then each 

 muscle again became tendinous for the extent of two inches, and 

 ultimately carneous again, prior to being inserted in the side of the 

 thyroid cartilage, and continued thence in the form of ^fascia into 

 the OS hyoides. 



Mr. Owen observes that this alternation of a non- contractile with a 

 contractile tissue, as exhibited by the above structure, displays in a 

 most striking manner the use of tendon in regulating the amount of 

 muscular contraction. Had the sterno-thyroideus been muscular 

 throughout its entire length, the contraction of its fibres would have 

 been equal to draw down the larynx and os hyoides to an extent quite 

 incompatible with the connections of the adjacent parts ; but the in- 

 tervention of long and slender tendons duly apportions the quantity 

 of contractile fibre to the extent of motion required. 



The ligamentum nuchce was remarkable for its prodigious develope- 

 ment ; it commenced at the sacral vertebrce, and receiving, as it ad- 

 vanced, accessions from each of the lumbar and dorsal vertebrae, be- 

 came inserted into the spinous processes of the cervical, the extreme 

 portion passing freely over the atlas, and terminating by an expanded 

 insertion upon the occipital crest. The bony attachment of the liga- 

 ment aflforded by the skull was raised considerably above the roof of 

 the cranial cavity, the exterior table of the skull being widely sepa- 

 rated from the vitreous plate by large sinuses, which commencing 

 above the middle of the nasal cavity extended as far posteriorly as be- 

 neath the base of the horns ; the sinuses were traversed by strong 



