REPTILES. 



fide, which are lafl in the lachrymal gland. The trunk is 

 afterwards divided into two branches: — one internal, which 

 correfponds to the fpheno-palatine and fub-orbitar nerve. 

 It fumifhes filaments to the palate and to the nofe ; and 

 when arrived at the anterior part of the orbit, it proceeds 

 outwardly and fprcads upon the face. The other branch of 

 the principal trunk is external ; it partes alfo upon the floor 

 of the orbit, to which it gives many filaments, and at length 

 ifluing from the inferior part of the orbit, it expands upon 

 the face, anailomofing with the other facial nerves. 



The inferior maxillary branch proceeds almofl vertically 

 downward to the polterior pa t of the orbit, before the 

 petrous and articular procefs of the os temporum. In its 

 courfe towards the lower jaw, it pad'es between the tem- 

 poral and pterygoid mufcles, to which it fends feveral fila- 

 ments. Having arrived at the lower jaw, before the arti- 

 cular furface, it enters the oblong aperture, and divides in 

 the fubltance of the bone. It forms feveral branches on 

 the inner part of the jaw, which are loll in the mufcles of 

 the tongue, and on the outfide fome others which ramify 

 under the (liin. 



The facial nerve exills in birds and reptiles, but its fize is 

 finall, becitiife thefe animals have no lips, and bccaufe their 

 mouth, as well as a great part of their face, is covered with 

 a horny or fcaly fubilance, in confequence of which tliele 

 parts have but little motion or fenfibility. We find, how- 

 ever, fome of the branches : they are not indeed ealily fol- 

 lowed in dilleAion, but their trunk always exifts. 



The auditory is united to the facial nerve as in the mam- 

 malia, and paifes into a meatus auditorius, whence its 

 branches go into the eaj". They will be defcribed in the 

 account of the ear. 



We have nothing remarkable to ftatre refpedf ing the par 

 vagtim or eighth pair of nerves in reptiles. We obferve 

 evidently that it is diltributed to the lungs, the heart, the 

 ocfophagus, and itomach, and that it forms plexufes on 

 thefe organs, in the fame manner as the great fympathetic 

 nerve produces them round all the arteries of the trunk. 

 On leaving the cranium, the par vagum forms decuilations 

 ■with the lingual and gloflo-pharyngeal nerves ; they after- 

 wards feparate from each otlier : the gloflb-pharyngeus is 

 pollerior, the par vagum in the middle, and the lingual an- 

 terior. The par vag'um does not always come out of the 

 cranium by a lingle hole ; it is formed of two or three fila- 

 ments, which afterwards rejoin, upon receiving a communi- 

 cating filament from the gloffo-pharyngeus, and one farther 

 down from the lingual ; the nerve then augments iomewhat 

 in diameter, and defcends into the breall. 



We have nothing to remark concerning the gloflo-pha- 

 ryngeal and hypogloffal nerves. 



Tortoifes have eight pair of cervical nerves, which are 

 diftributed nearly in the fame manner as in mammalia. The 

 three la(t pairs join in forming the brachial plexus. The 

 green lizard has four pair of cervical nerves, but only the 

 two lalt enter into the compofition of the plexus. In fala- 

 mandera :ind frogs the cervical nerves cannot be properly 

 diftinguilhrd from the dorfal, as the animals have no ribs. 

 A pair comes out between the firll and fecond vertebra;, 

 which is fent to the mufcles of the inferior part of the neck, 

 and under the fkin that covers them. Thefe nerves alfo 

 afford fome filaments to the flioulder. From this dillribu- 

 tion they may be regarded as real cervical nerves. In frogs 

 only two pairs enter into the compofition of the plexus. In 

 the falamander there are dillinftly four. 



We refer to the tables v.'iich indicate the nHinber of 

 the vertebra in reptiles, in wder to (hew the number of 

 nerves which iflue from their foramina, The difhibutiou 



of thefe nerves is the fame as in other animals, and to point 

 it out would be only repeating what we have already de. 

 fcnbed in man. 



Nerves of the front Limbs. — In the tortoife the three lad 

 pairs of cervical nerves, and the firft of the dorlal, proceed 

 to the thoracic member, where they form a plexus in the 

 following manner : the fifth cervical pafTes behind the other 

 four pairs, erodes them in their courfe, and unites with them 

 in its palFage. It then turns round the fcapula, which in 

 this animal is articulated with the firft dorfal vertebra. We 

 fhall return to the dcfcription of this nerve. The fixth 

 cervical pair proceeds diredlly along the fcapula on its in- 

 ternal furface : it is eroded pofteriorly by the fifth, and to- 

 wards the lower third of the fcapula receives the feventh 

 cervical pair. The feventh is flender, eroded by the fifth 

 and the firft dorfal pair, and united with the fixth, in the 

 manner we have pointed out. The firft dorfal pair partly 

 joins the feventh cervical, almoft at the point where it comes 

 out of the vertebral canal ; it is then fent to the mufcles of 

 the Ihoulder. 



We (hall now purfue each of the cords we have mentioned 

 to their termination. 



The large nerve produced by the fifth cervical pair, hav- 

 ing arrived behind and near the true articulation of the fca- 

 pula with the fpiiie, divides into three branches ; one, which 

 is but a filament, appears to be diftributed to the articular 

 capfule ; a fecond, which is very flat, and from the fides of 

 which a vail number of leder branches extend to the mufcles 

 of the d<in, appears to take the place of the mufculo-cu- 

 taneus ; the third branch, which accompanies the mufcles 

 of the fcapula under the fkin, defcends to the humerus, 

 without producing any remarkable branches. At this place, 

 however, it fends off feveral ramifications to the extenfor 

 mufcles of the fore-arm. The trunk continues its direction 

 forward, expands and lofes itfelf under the fkin, and may 

 be followed as far as the hand : it may, perhaps, be re- 

 garded as fupplying the place of the ulnar nerve. 



The fixth pair of cervical rerves having, as we have 

 fhewn, afliited in forming the brachial plexus, paffes along 

 the internal furface of the fcapula ; about the lower third 

 of that bone it receives the feventh pair ; the nerve then be- 

 comes thicker, but foon after divides into two branches ; 

 one, which is flender, pades into the groove, between the 

 furca and the clavicle, and then fpreads over the articular 

 caplule of the humerus, after furnifning numerous filaments 

 to the mufcles which furround it ; the nerve may be regarded 

 as analogous to the articular in man. The trunk of the 

 nerve, which evidently fupplies the place of the median, 

 upon reaching the articulation of the humerus with the 

 fcapula, tranfmits filaments to the adjoining mufcles. On 

 arriving at the palmar furface of the fore-arm, it divides 

 into three portions, two of which are on the ulnar fide, and 

 fink deeply into the mufcles ; the third, which is much 

 larger, follows the radial fide of the fore-arm, and at the 

 bafe of the thumb proceeds to the palm of the hand, and 

 detaches filaments to each of the fingers. 



The feventh cervical pair unites, as we have ftated, to 

 the fixth, at the pollerior part of the fcapula, to form the 

 median and articular nerves. We have, therefore, no oc- 

 cafion to return to its defcription. The firft dorfal pair is 

 loft in the mufcles of the flioulder, and is not continued 

 throughout the arm. 



The brachial plexus of the lizard differs a little from that 

 of the tortoife ; it is formed by two dorfal, and the two 

 laft cervical pairs : the firll of the cervical furnilhes only 

 one of its branches to the plexus ; the other going to the 

 neck. 



In 



