REPTILES. 



expoffd to the atmolphere, in very cold climates, do not die, 

 is a point which Mr. Hunter docs not pretend to determine ; 

 not knowing tlie difference, he fays, between the effefts of 

 a natural and artificial cold. Ibid, p. 89, 90. 



" The experiments of Mr. Hunter farther prove that the 

 temperature of moll of the foregoing animals not only 

 falls rapidly in a colder medium, but that it rifes more 

 quickly in a warmer one than that of thoie which poffefs a 

 higher ftandard temperature. In the llomach of a frog, 

 the thermometer rofe from 45-' to 49° ; the animal was then 

 placed in an atmofphere made warm by heated water, where 

 it remained for 20 minutes, and upon introducing the ther- 

 mometer again into the ftomach, the mercury rofe to 64'^. 

 (Ibid. p. 90.) A healthy viper was put into an atmofphere 

 of io8^ and,-in fcven minutes, the heat of the animal, both 

 in the ftomach and anus, was found to be gz°.^, beyond 

 which It could not be raifed in the above heat. An eel, 

 very weak, whofe heat was 44°, which was nearly that of 

 the atmofphere, was put into water heated to 65°, for fifteen 

 minutes ; and, upon examination, it was of the fame degree 

 of heat with the water. The heat of a tench was, in ten 

 minutes, raifed from 41° to 55°, both in the ftomach and 

 redlum, by being put into water at 65°. 



" He found alfo, that a living and dead tench, and a living 

 and dead eel, put together into warm water, received heat 

 equally fall ; and when they were expofed to cold, both 

 the living and the dead admitted the cold likewife with equal 

 quicknefs. (Ibid. 104, 105.) Hence, therefore, the 

 animal heat, in all the claffes of animals hitherto mentioned, 

 whether they inhabit the air or the water, feems to follow 

 nearly that of the medium in which they are placed ; and 

 their ftandard temperature cannot, in confequence, be 

 reftriftedto any fixed point, but muft be confidered always 

 in relation to that of their furrounding medium. 



" Notwithftanding, however, the low degree of heat which 

 thefe feveral claffes of animals poffefs, hardly, in fome in- 

 ftances, exceeding that of the medium in which they live, 

 yet this fmall excefs is a proof that they poffefs, within 

 themfelves, a power of producing heat. The lofs of heat 

 which infefts fuffer under cold, the fall of temperature 

 which many of the vermes clafs undergo from the fame 

 caufe, the melting of fnow by the heat of fifties, and the 

 decline of animal heat which the amphibia, when expofed 

 to great cold, experience, all demonftrate that the fur- 

 rounding medium, whether it be air or water, is conftantly 

 drawino- off their heat, which renders neceffary as conftant 

 a re-produAion of it." P. 218 — 221. 



The great fize and beautiful ftrufture of the lungs of 

 reptiles lead us to conclude that they are very important 

 organs in the economy of thefe animals, although their ufes 

 and relations are not yet all fatisfaftorily afcertained. It 

 feems tolerably certain, that befides their office as refpiratory 

 organs, they render the body lighter for fwimming in many 

 inftances : in this point of view they may be compared to 

 the fwimming bladder of fifti. It is by the inflation of its 

 large lungs, that the cameleon can diftend its body fo re- 

 markably. 



" The lungs, too," fays Blumenbach, " are fubfervient in 

 many reptiles to the produftion of found ; — I fay in many, 

 becaufe fome fpecies, even of our reptiles, are, fo far as I 

 know, completely dumb : viz. the falamander, lacerta agilis 

 (green lizard), and anguis fragilis (blind-worm) ; and others 

 utter found very rarely, and only when in great danger, as 

 the water newts ; refembling, in that refpeft, the mole and 

 hare, which do not cry out until great violence is offered 

 them. 



" It has-been reported that fome mammalia lofe their voice 



I 



in particular fituations, as dogs in certain parte of America : 

 the fame thing has been reported of reptiles, for example 

 frog;, which G. F. Miiller found to be dumb in many 

 regions of Afiatic Ruifia. iSammlung Ruffifcher Gefchich- 

 ten, vii. p. 123." Blumenbach, Specimen, &c. p. 15. 



Organs of Voice. — The larynx, varying in different genera, 

 as in the other claffes, has thefe cliaraftcrs in common ; w'z. 

 that it has no epiglottis, and is compofed of pieces ana- 

 logous to thofe of the upper larynx of birds. This is the 

 only vocal organ ; tlicrc is ix-ver an inferior larynx, as in 

 birds. The voice cannot be modified by lips or velum 

 palati, fince they do not exift. The degree of aperture 

 of the mouth, and the motions of the tongue, are alone 

 capable of modifying the action of the larynx. 



The cartilaginous flieleton of the crocodile's larj'nx con- 

 tains five pieces : a nearly fquare plate, compofing all the 

 under furface of the cavity. Two circular pieces or han- 

 dles, fixed near together at one end, in the middle of the 

 front edge ef the plate, and at the other, in the middle of 

 the fide. Their body is a little evelated above the fquare 

 plate, and leaves on eacli fide, between it and that plate, a 

 membranous hollow. The anterior extremity of each piece 

 forms a lateral and vertical prominence, conftituting a kind 

 of pillar under the glottis. To the pofterior external angle 

 of this plate, a branch is fixed on each fide ; thefe join 

 together above, and form, with the back edge of the plate, 

 a complete ring, which is the beginning of the trachea. 



The glottis IS merely membranous, extending from the 

 junftion of the two laft-mentioned branches to the middle 

 of the OS hyoides, where the membranes compofing it 

 are attached. There are neither ventricles nor chordx 

 vocales. Two mufcles aft on this apparatus. One comes 

 from below the great plate, furrounds the larynx, afcend- 

 ing obliquely backwards, and joins the correfponding 

 mufcle of the other fide behind the glottis, which it has 

 the power of clofing. The other comes from below the 

 back edge of the fame plate ; decuffates the former, afcend- 

 ing obliquely forwards, and is fixed to the edge of the 

 glottis, which it opens. The firft half of the glottis cor- 

 refponds then to the broad and flat cavity of the larynx ; 

 the fecond, beginning from the two pillars in front, is 

 merely a long and narrow flit. It is only in ftriking againft 

 the two pillars, that the air can produce a whiftling noife, 

 if indeed any fuch be produced at all. 



The glottis of the crocodile of the Orinoco, fays Hum- 

 boldt, is furrounded by a thick fiefhy ring with circular 

 fibres, which the animal can contract to fuch a degree, that 

 the flit or opening of the trachea cannot be diftinguifhed. 

 -The glottis refts on a round and flat cartilage, analogous 

 to the thyroid of mammalia. The upper part of the 

 trachea prefents a fingular ftrufture, which we mention 

 here, becaufe it feems fubfervient to the produftion of 

 found. The firft nine cartilages are not complete rings, 

 but are joined together above by a tranfparcnt, very fine 

 and tenfe membrane. (See Humboldt Recueil d'Obfer- 

 vations de Zoologie et d'Anatomie comparee, t. i. pag. 11. 

 pi. 4.) Geoffroy obferved ten annuli thus united in the 

 Nilotic crocodile ; Duverney fixteen, in a crocodile diflefttd 

 at the Academy of Sciences, and the Jefuit Miffionaries in 

 Siam a larger number. To this membrane, ftretched like 

 the parchment of a drum, and thrown into vibrations by 

 the air, the deep and terrific bowlings or bellowings of 

 thefe dangerous reptiles are afcribed ; the glottis being at 

 the fame time clofed by its mufcular ring. Annales du 

 Mufeum, t. 2. p. 46. 



In the iguana, the pillars are fcarcely more prominent 

 within than the reft of the parietes ; the glottis is very 



ftiort. 



