184 DE. J. IVrCTRrE ON THE FOKM AND STEUCTUEE OF THE MANATEE. 



the main nerve goes down the neck, and on the right side crosses the subclavian artery 

 ere dipping into the thorax. 



A descendens noni lies alongside the latter, and appears to issue from the same foramen. 

 It has a doubtful ganglion and a branch communicating with the pneumogastric, the 

 hollow of exit lying inside the stj'lo-hyal. 



A hypoglossal nerve pierces the inner portion of the parotid gland, and passes forwards 

 and round the carotid artery lying upon the surface and inner border of the stylo-hyoid 

 muscle. There is a long recurrent laryngeal branch on each side. 



The facial nerve is of large size, and escapes from the skull at the stylo-mastoid 

 foramen. It passes over the paramastoid process and the meshwork of vessels behind the 

 angle of the jaw, here piercing the substance of the parotid gland. It passes forwards 

 over both portions of the masseter muscle, and goes under the fossa of the downward 

 portion of the malar arch, where it is distributed on the surface of the buccinator and 

 other facial muscles. 



The cervical and brachial plexus of nerves. In discussing the number of cervical 

 vertebrae, as opposed to De Blainville's statement that there are seven, Stannius says^, 

 " I counted also only seven pairs of cervical nerves ; the strong phrenic nerve arises 

 from a bundle of the third and fourth cer^dcal nerves, but it also receives a strongish 

 bundle from the second. The brachial plexus arises from bundles of the anterior 

 branches of the fifth, sixth, and seventh cervical and the first dorsal nerve ; the bundles 

 of the sixth and seventh cervical nerves are thick and strong ; but the fifth cervical and 

 first dorsal nerve are weak and thin." 



From the very elaborate reticular network of minute blood-vessels (which in the 

 male specimen I injected with tolerable success) I encountered some difficulty in tracing 

 the nerves issuing from the cervical foramina, but, with patience, I unravelled the inter- 

 woven tissues, and was rewarded with a fair view of them. Figs. 29 & 30 exhibit their 

 relations ; but the fiist, or suboccipital twig, is hidden by the vascular rete in the latter 

 figui-e. The following are my notes of the dissection : — The first nerve, of small size, 

 comes out between the rectus lateralis and rectus anticus minor muscles and gives twiss 

 to them and the neighbouring parts. The second nerve, much thicker than the first, 

 issues between the atlas and axis, and crosses over the atloid attachment of the serratus 

 magnus muscle, and then over the lateralis to the anterior border of the shoidder, giving 

 branches to the suprascapular and other muscles in that region. The third cervical 

 nerve emerges between the second and third vertebrte, posterior to the upper (larger) 

 tendon of the scalenus, but anterior to the diminutive additional tendon which is 

 inserted along with the larger into the axis — the same spoken of in discussing the 

 absent neck-vertebra. It divides into several filaments, and is distributed to the 

 shoulder-region like the second. Twigs connect the second and third and fourth 

 nerves. The fourth nerve, smaller than the second and third, but rather larger than 



' Op. cH. p. 8. 



