and of others added, like to what is obfervable in fishes; whofe pofture in the waters resembles that of birds in the air, and both very different from man and beafts; and laftly, to hint at no more, I might furvey the peculiar ftructure of the larynx, the tongue, the inner ear h, and

many

oribus longe diverfa, tamen inter fe, quoad præcipuas lynspare partes, fymbola reperiuntur.' The particulars wherein the brains of birds and fishes agree with one another, and wherein they differ from the brain of man and beaft, fee in the fame juftly famous author, Willis. Cereb. Anat. c. 5.

Circa bifurcationem afperæ arteriæ, elegans artificis libere agentis indicium detegitur ex avium comparatione cum quadrupedibus: cum vocis gratia in diverfis avibus diverfam mufculorum ⚫ fabricam bifurcationi afperæ arteriæ dederit, quorum nullum veftigium extat in homine et quadrupedibus mihi vifis, ubi omnes ⚫ vocis mufculos capiti arteriæ junxit. In aquila, etc. fupra bifur 'cationem,' etc. Steno in Blaf. Anat. Animal. p. 2. c. 4.

f The afpera arteria is very remarkable in the fwan, which is thus described by T. Bartholin, viz. Afpera arteria admirandæ fatis ftructura. Nam pro colli longitudine deorfum cefophagi comes protenditur donec ad fternum perveniat, in cujus capfulam fe incurvo flexu infinuat et recondit, velut in tuto loco et theca, moxque ad fundum ejufdem cavitatis delata furfum reflectitur, egrediturque anguftias fterni, et claviculis mediis confcenfis, quibus ut fulcro nititur, ad thoracem fe flectit-Miranda hercle modis • omnibus conftitutio et refpirationi infervit et voci. Nam cum in • ftagnorum fundo edulia pro viêu quærat, longiffimo indiguit collo, ne longa mora fuffocationis incurreret periculum. Et certe dum dimidiam fere horam toto capite et collo pronis vado immergitur, pedibus in altum elatis coloque obverfis, ex ca arteriæ • quæ

many matters befides; but for a fample, I fhall only infift upon the wonderful provifion in the bill for the judging of the food, and that is by peculiar

quæ pectoris dictæ vaginæ reclusa est portione, tanquam ex condo promo fpiritum haurit. Blaf. ib. c. 10.

The ftructure of the tongue of the wood-pecker is very fingular and remarkable, whether we look at its great length, its bones and muscles, its encompaffing part of the neck and head, the better to exert itself in length, and again, to retract it into its cell; and laftly, whether we look at its sharp, horny, bearded point, and the glewy matter at the end of it, the better to ftab, to stick unto, and draw out little maggots out of wood. Utilis enim picis (faith • Coiter) ad vermiculos, formicas, aliaque infecta venanda talis lingua foret. Siquidem picus, innata fua fagacitate cum deprehendit alibi in arboribus, vel carie, vel alia de caufa cavatis, vermes infectaque delitefcere, ad illas volitat, fefeque digitis, ungulifque pofterioribus robuftiffimis, et cauda pennis rigidiffimis fuftentat, donec valido ac peracuto roftro arborem pertundat: arbore pertufa, foramini roftrum immittit, ac quo animalcula ftridore ⚫ excitet percellatque, magnam in arboris cavo emittit vocem, infecta • vociferatione hac concitata huc illucque repunt; picus vero linguam 'fuam exerit, atque aculeis hamifque animalia infigit, infixa attrahit et devorat.' Vide Blafii, ubi fupra, p. 2. c. 24.

I have before, in book iv. chap. 3. taken notice of what others have observed concerning the inner ear of birds, referving my own obfervations for this place which I hope may be acceptable, not only for being fome of them new, but alfo thewing the mechanifm of hearing ing eneral.

In this organ of birds, I fhall take notice only of three parts, the membranes and cartilages; the columella; and the conclave, the drum, as fome call it, or membrana tympani, as others, confifts of two membranes, the outer, which covers the whole meatus, bafon,

C 4

peculiar nerves lodged therein for that purpofe; fmall and lefs numerous in fuch as have the affiftance of another fenfe, the eye; but large,

more

bafon, or drum, as fome call it, and the inner membrane. To fupport, diftend, and relax the outermoft, there is one fingle cartilage, reaching from the fide of the meatus, to near the middle of the membrane. On the top of the columella is another cartilage, confifting of three branches, a, b, c, in Fig 23. The longeft middle branch, a, is joined to the top of the fingle upper cartilage before spoken of, and affifts it to bear up the upper outer membrane: the two branches, b, e, are joined to the os petrofum, at some distance from the outer membrane: upon this inner cartilage, is the inner membrane fixed, the two outer fides of which, a, b, and a, e, are joined to the outer membrane, and make a kind of a three fquare bag. The defign of the two branches or legs of the cartilage, b, c, are, I conceive, to keep the cartilage and columella from wavering fide ways, and to hinder them from flying too much back; there is a very fine flender ligament extended from the oppofite fide, quite across the meatus or bafon, to the bottom of the cartilage, near its joining to the columella. Thus much for the membrana tympani, and their cartilages.

The next part is the columella, as Schelhammer calls it. This is a very fine' thin, light, bony tube; the bottom of which spreads about, and gives it the refemblance of a wooden pot lid, fuch as I have seen in country-houses. It exactly fhuts into, and covers a foramen of the conclave, to which it is braced all round, with a fine fubtle membrane, compofed of the tender auditory nerve. This bottom or bafe of the columella, I call the operculum.

The laft part, which fome call the labyrinth and cochlea, confifting of branches more like the canales femicirculares in man, than the cochlea, I call the conclave auditus. It is, as in most other animals, made of hard context bone. In most of the birds I have opened, there are circular canals, fome larger, fome leffer, croffing

one

more numerous, and thickly branched about, to the very end of the beak, in fuch as hunt for their

one another at right angles, which open into the conclave. But in the goofe it is otherwife, there being cochleous canals, but not like thofe of other birds. In the conclave, at the fide oppofite to the operculum, the tender part of the auditory nerve enters, and lineth all those inner retired parts, viz. the conclave and canals.

As to the passages, columnæ, and other parts obfervable in the ear of birds, I fhall pass them by, it being fufficient to my purpose, to have described the parts principally concerned in the act of hearing. And as the ear is in birds the moft fimple and incomplex of any animal's ear; fo we may from it make an easy and rational judgment, how hearing is performed, viz. found being a tremor or undulation in the air, caufed by the collifion of bodies, doth, as it moves along, ftrike upon the drum, or membrana tympani, of the ear which motion, whether ftrong or languid, fhrill or foft, tuneful or not, is at the fame inftant impreffed upon the cartilages, columella, and operculum, and fo communicated to the auditory nerve in the conclave.

And now if we compare the organ and act of hearing with those of fight, we shall find that the conclave is to hearing, as the retina is to fight; that fonorous bodies make their impreffions thereby on the brain, as visible objects do by the retina. Alfo, that as there is an apparatus in the eye, by the opening and fhurting of the pupil, to make it correspond to all the degrees of light, fo there is in the ear, to make it conformable to all the degrees of found, a noble train of little bones and mufcles in man, &c. to ftrain and relax the membrane, and at the fame time to open and fhut the basis of the ftapes (the fame as what I call the operculum in birds :) but in birds there is a more fimple but fufficient apparatus for this purpose, tender cartilages, instead of bones and joints, to correfpond to the various impreffions of founds, and to open and fhut the operculum. Befides which, I fufpect the ligament I mentioned, is only the tendon of a muscle, reaching to the inner membrana tympani, and

their food out of fight in the waters, in mud, or under groundi.

AND now from the head and mouth, pafs we to its near ally, the ftomach, another no lefs notable than useful part; whether we confider the elegancy of its fibres and muscles, or its multiplicity; one to foften and macerate, another to digeft; or its variety, fuited to various foods, fome membranous, agreeable to the frugivorous,

joined thereto, as I find by a stricter scrutiny, and not to the cartilage, as I imagined. By this mufcle, the inner membrane, and by means of that the outer alfo, can be diftended or relaxed, as it is in man, by the malleus and its muscle, &c.

iFlat-billed birds, that grope for their meat, have three pair of 'nerves, that come into their bills, whereby they have that accuracy to diftinguish what is proper for food, and what to be re'jected by their tafte, when they do not fee it.

This was moft evi

⚫ dent in a ducks bill and head; ducks having larger nerves that ⚫ come into their bills than geefe, or any other bird that I have feen; and therefore quaffer and grope out their meat the most. But then I difcovered none of thefe nerves in round-billed birds. But • fince, in my anatomies in the country, in a rook, I first observed two nerves that came down betwixt the eyes into the upper bill, but confiderably smaller than any of the three pair of nerves in the bills of ducks, but larger than th nerves in any other roundbilled birds. And it is remarkable that thefe birds, more than any round billed birds, feem to grope for their meat in cow-dung,' &c. Mr. J. Clayton, in Philofo. Tranf. No. 206.

• I observed three pair of nerves in all the broad-billed birds that I could meet with, and in all fuch as feel for their food out of fight, as faipes, woodcocks, curlews, geefe, ducks, tcals, widgeons, &c. These nerves are very large, equalling almoft the optic