THE NERVOUS SYSTEM L\ BIRDS. 791 



Common mcitores oculorum. I'ulhilici. External motorft oculorum. There is nothing 

 particular to lie citi d reflecting the.-e. 



Triiji miaul nrrvf. This nerve divides into three principal branches, as in the 

 .loinr-ti.-a 1 ' d animals. Tlie ophthalmic branch has a nasal minuscule that becomes 

 Mip< nicial, and extends to tin extremity of (lie luk; as well as a third filament that 

 i.- l--.-t around the interior oriliee of the nasal cavities. 



Thu superior nuisiUanj issues from the cranium by the opening through \vhicli the 

 lower maxillnry nerve passes, creeps helow the orbit, traverses the, maxillary hone, an i 

 terminates on the sides of the beak by filaments that resemble the infra-orbital 

 ramn.-eiiles of the Hor.-i-. 



The inferior maxillary furnishes two branches : one passi s through the dental canal 

 and.arrives at the extremity of the lower mandible; the other is spread in the sub- 

 oorneus integuments of the same. 



ial nerve. This is small in birds. "It is distributed to the muscles of the juws 

 anil the small muscles which erect the feathers of the crest.'' Cuvier. 



Glosso-pharynaeal nerce. This calls for no remark. 



1'neumogastric nerve. There are few differences observed in this; it is as extensive 

 as in mammals, and its anastomoses and relations are nearly the same. It is not en- 

 tirely formed at its exit from the cranium, and always offers two or three constituent 

 filaments that join it, and are confounded at some distance from the point of emergence. 

 The recurrents furnish ramuscnles to the crop. 



^jiinul accessory nerve. This likewise has a medullary root that appears at the 

 third cervieal vertebra ; it runs along with the vagus nerve to become superficial. 



Hiifintjlnxsal nerve. The same origin as in quadrupeds. Where it crosses the pneu- 

 mogastric, it detach* s a long filament that passes along with the jugular vein towards 

 the chest. On the sides of the larynx it bifurcates ; one branch proceeds forward 

 beneath the tongue, the other follows in the same direction, but on the upper surface of 

 that organ. 



SriXAi. NI:UVK.S. We need only notice the nerves of the wing and pelvic limb, the 

 others being disposed in a similar manner to those above described. 



Brachial plexus. Three principal branches the last cervical and first two dorsal 

 form this plexus in Palmipeds ; in the Gallinacex there are four the last three 

 r\ ioal and first dorsal. These branches anastomose beneath the deep face of the 

 scapulo-liumeral articulation. When fully constituted, the plexus gives oft' some col- 

 lateral ramuscules, and terminates by two fasciculi of branches. The first collateral 

 goes to the deep ixK-toral muscle : another is distributed to the muscles surrounding the 

 head of the humerus, as well as to the articular capsule. The fasciculi of terminal 

 branches may be distinguished, after their situation, as anterior and jwsterior. The 

 latter represents the internal cutaneous and radial nerve; it gives off muscular and 

 cutaneous iiimu-eules that extend to the digits at the extremity of the wing. The 

 anterior fasciculus is larger, and is also extended to the whole of the limb, being ex- 

 pended in motor and sensitive filaments ; near its origin it furnishes ramuscules to the 

 Mip< -rticial pectoral musele. This fasciculus represents the median, ulnar. and anterior 

 intr/n'ul, or museulo-cutaneous of mainniiils. 



I. uinoo-sacral plexus. Two lumbar and four sacral nerves constitute tl is plexus. 

 In the /''./ it is distinctly divisible into two portions, an anterior and posterior, 

 considerably wide ap.irt. 



The unt~< rinr fH,rt,'im is composed of the lumbar branches and a portion of the first 

 sacr.d ; their fusion takes place on the salient bony ridge that separates the lumbar 

 from tin- .-acnil ri-L'ions. It gives origin to four or five hnmche.-. unions which are 

 cli-.irly discernible: 1, Ajilaiiu-iit to t lie fascia lata muscle ; 2, A crural T j'< moral nerve; 

 3, An internal sajihtu' ut descends to the leg; 4, An olituratur nerve. The 



latt.-r i-* v. rv -1. nder, and directed downwards and backwards, passing into the muscle 

 that closes the obturator foramen. 



The posterior i-ortimt comprises a portion of the first sacral, and the whole of the 

 -iiccecding nerve.-. Th. > are directed outward.-, to\\ai.U ib.- ~.- K itic notch, where 

 they unit- ; during their course in the interior of the pelvis, they are surrounded by the 

 f the kidney. Ti. distribution of this |N>rtioii of the plexus rt'St-niblcs tl. 



Thu-.' in leaving the sciatic notch, it gives off the anterior and posterior 

 !llntr,il .//-.*. then two long branches that lie together as far as tin- geiiiclli ; these 

 branch.- an : 1. 'I he ,jr, .it sciatic, with a ramUM-nl. |. Hi and the interior 



tibial mii.-cl.,; -2. The rsl-mal y,y.//V< '.i/. \\ hich, out-i.le the superior ( .\tn rnity o! tlu- 

 It ir. di\id.'.^ into tin- nt'ifculo-culaneous and anterior tibial nevn 



