36 DR. J. MURIE ON THE MANATEE, 
memoir!) dividing the nerves issuing from the one foramen. On the contrary, on the 
left side I did not observe the presence of such a minute tendon. But though to appear- 
ance absent, there was nevertheless a band of fascia, evidently belonging to the deep 
cervical fascia, which took the position of the minute tendon in question. 
The third cervical nerve, then, distinctly issues from the foramen between the axis 
and the succeeding vertebra. It passes thereafter outwards and over the scalene, joins, 
as aforesaid, the loop of the second nerve, and courses somewhat parallel with the 
branches of the latter. Its main trunk subdivides terminally into branchlets, which are 
distributed to the trapezius and other parts of the neck above and around the scapula. 
IV. From the same foramen as the last, viz. between the axis and the succeeding 
vertebra, is another nerve-trunk, which within the vertebral foramen unites with the 
preceding by fascia or, it may be, nervous tissue. ‘This I ascertained after I had made the 
dissection and had the drawing done represented in Pl, VIII. fig. 5, when I followed 
the nerves right into the vertebral canal and through the theca of the spinal cord. 
But inasmuch as the dissection was a laborious proceeding, taking some days to finish, 
likewise from the animal having died after an exhausting illness with the nervous tissue 
tender in some places, and particularly from the great difficulty of cleaning the parts 
around the intervertebral foramen and within the spinal canal, owing to the presence 
of the rete mirabile, I could not trace the nerves distinctly as separately arising from 
the spinal cord itself. 
However this may be, it is certain that immediately exterior to the intervertebral 
foramen the fourth and the third cervical nerves are quite distinct and trend in different 
directions. The third takes an upward and forward, the fourth a downward and back- 
ward course. These two nervous cords are nearly of equal calibre, and barely as thick as 
is the second nerve. ‘Tracing the course of this fourth nerve outwards, I found that 
fully one inch beyond its exit from the intervertebral foramen it forms a union with a 
division of the fifth nerve. At this junction the phrenic nerve is given off; and it 
descends (is directed rearwards) as usual into the chest, lying superficially to the brachial 
plexus. Beyond the junction just mentioned the calibre of the compound nerve is 
considerably increased, and it splits up into three divisions. 
One proceeds above the shoulder-joint, passes over the suprascapularis muscle, and 
supplies the parts on the upper and outer side of the shoulder, including the trapezius 
&c. The second division goes to the outer head of the humerus, being chiefly distri- 
buted to the pectoralis major and the deltoid, ina manner therefore equivalent to a 
supraclavicular branch. The third, deepest nerve-division pierces the tissues betwixt 
the subscapularis and the supraspinatus, and it goes to the fleshy parts at the back of 
the scapula, twigs penetrating the supraspinatus &c., and another proceeding through 
the suprascapular notch. 
Comparing what has now been said with the general distribution of the cervical 
* Op. cit. pp. 137, 152, & 184, pl. xxiv. fig. 29. 
