232 MR. R. OWEN ON THE ANATOMY 
careful dissection of the left recurrent nerve. The nervus vagus as it passes down in 
front of the arch of the aorta sends off four small branches, which bend round the arch of 
the aorta on the left side of the ductus arteriosus ; the two small branches on the left side 
pass to the esophagus and are lost in the cesophageal plecus ; the remaining two branches 
continue their recurrent course, and ascend upon the side of the trachea, giving off fila- 
ments which communicate with branches from the neighbouring cesophageal nerves: 
these recurrent filaments also receive twigs from the cesophageal nerves, and thus in- 
crease in size, and ultimately coalesce into a single nerve of a flattened form, which 
enters the larynx above the cricoid cartilage and behind the margin of the thyroid 
cartilage. I may observe, that hitherto the Giraffes have not been heard to utter any 
vocalized sound, except once in the case of the male during the cottus. 
The sympathetic nerve in the neck presents five ganglionic enlargements,—the two 
lowest are moderately large, the next above is smaller, the fourth, counting from below, 
still less, and the fifth is again large and elongated. 
Muscles. 
No peculiarity of importance was noticed in the dissection of the abdominal muscles ; 
the aponeurosis of the external oblique was thick and elastic, as in many other Ruminants 
and Pachyderms, which, from the nature of their food, require support for large accu- 
mulations of it, and proportionally developed alimentary sacs. 
The mylo-hyoideus is a thick and strong muscle ; it arises from the whole of the in- 
ternal surface of the lower jaw, and is inserted principally into the raphe, or longitu- 
dinal commissure dividing it from its fellow of the opposite side. It adheres firmly to 
the genio-hyoideus: this arises by a well-marked tendon from the posterior rugous sur- 
face of the symphysis menti, and has the usual insertion. The genio-glossus arises by a 
tendon close to the inner side of the tendon of the genio-hyoideus ; its fleshy belly has 
a considerable antero-posterior extent, and diminishes to a very thin edge at its anterior 
margin. The digasiricus has the usual origin, and is inserted broad and thick into the 
under side of the lower jaw. ‘The stylo-hyoideus is external to the digastricus, and is 
remarkable for the slenderness and length of its carneous part. ‘The disposition of its 
fibres and of those of the other muscles which combine to form the fleshy substance of 
the tongue, have already been described. The most interesting modifications in the 
muscles of the os hyoides were found in those which retract that bone. The muscle 
which, as in some other Ruminants, combines the offices of sterno-thyroideus and sterno- 
hyoideus, arises in the Giraffe by a single long and slender carneous portion from the 
anterior extremity of the sternum ; this single fleshy origin is nine inches long, and ter- 
minates in a single round tendon, which is six inches long; the tendon then divides into 
two, and each division soon becomes fleshy, and so continues for about sixteen inches : 
then each division again becomes tendinous for the extent of two inches, and ultimately 
carneous again, when it is inserted into the side of the thyroid cartilage, and is thence 
