REPTILES. 



a ridge towards the anterior part, received into a cor- 

 refponding concavity of tlic lower jaw. 



Safmnry Glands. — We liavc already obfervcd, tliat no- 

 tiling defcrvinjT the name of mallication takes place in 

 :iny reptile. They live on other animals, and almolt uni- 

 vciHiIly fwallow them whole. Some teitudines feed on 

 liiell-fini, and break the teftaceons coverings witli their 

 horny mandibles, but they do not chetu the contained ani- 



i.ils. The falivary apparatus mult, therefore, be very dif- 

 ' rent from that of the mammalia. 



Several reptiles, however, require the afliftance of fluids 

 poured into the mouth for feizing and fwallowing their 

 prey. Some, as the frog and cameleon, dart out the tongue, 

 covered with a vifcid matter, upon infefts, which are en- 

 tangled in the flimc, and thus captured. Serpents fpread 

 a frothy flaver over the animals which they fwallow, to 

 facihtate their paflage. 



In fome reptiles the tongue is compofed, in great part, 

 of a thick glandular mafs, formed of numerous fmall tubes 

 united at their bafes, and feparaling towai-ds the furface of 

 the tongue. They are fo many papilla, giving a bridly 

 appearance to the organ, or rendering it villous, when they 

 are very fmall. The fides of the mals are perforated by 

 numerous pores, thiough which the fecreted fluid cfcapes. 

 This gland refts on the mufcles of the tongue, and follows 

 the motions, which they communicate to the organ. The 

 gland in qucftion exifls in the chelonians ; in the teftudo 

 grasca the llru£lure juft defcribed is very evident. It exifts 

 alfo in feveral fauriaiis, as the flat-headed gecko (G. fim- 

 briatus), the common iguana, and the Schneiderian fcink. 



In the agame umbra (iguana umbra, Linn.) the gland 

 is furmounted in front, inftead of papillx, with tranfverfe 

 plates clofely arranged. Thefe lamina; cover the whole 

 furface in the cameleon. 



The tongue feems to be covered by an analogous glan- 

 dular fubllance in the batracians. 



Where the tongue is fcaly, or fmooth, asd covered with 

 a fimple membrane, the place of this gland is fupplied by 

 two others, elongated and glandular, fituated under the 

 Ikin, along the external furface of the branches of the 

 lower jaw-bone, and pouring out their fluid at the outfide of 

 the teeth of the fame jaw. In this direftion they are in 

 contaft with the palatine membrane. Thefe glands are 

 ftrongly marked in the tupinambes, the colubres, and the 

 boas. In the amphifb;enae the glands are not fituated in 

 the fame place, although they have the fame apparent ftruc- 

 ture. They lie immediately under the tongue, between the 

 genio-glofh and genio-hyoidei. 



The conglomerate gland lecreting the poifonous fluid of 

 the venomous ferpents is fpoken of in the defcription of 

 the teeth. 



The OS hyo'ides varies in the different orders of reptdes, 

 but it approximates in general very nearly to that of birds, 

 from which it does not differ elTentially in the faurian and 

 ophidian orders. As in birds, its connections with the 

 larynx are very inconfiderable : there is no niufcle pafling 

 between them : a ilmple membrane is the medium of union. 

 They are, in faft, completely feparated in fome genera of 

 faurians ; as, for example, the cameleon : and the fame 

 obfervation may be extended to all the ophidians which 

 have a tongue included in a fheath. This circumftance 

 completes the proof of what is rendered very probable by 

 many other reafons, that the eflential fur.ilion of the OS 

 hyoides is to fupport the tongue, and affift its motions. 



The form of the os hyoides varies much in the chelo- 

 nians : fometimes the body is nearly fquare, thin, and flat- 

 tened, then the pofterior cornua are ftraight, articul.iti.d to 



13 



the poilerior angles of the body, feparating from each 

 other as they pafs backwards, and liaving the larynx placed 

 in their interval. The anterior coniua are confolidated to 

 the body, a little behind tlie anterior angles, directed back- 

 wards, and curved upwards beliind the occiput. In front 

 tliebody is prolonged into a point, under the tongue, which 

 it fupports. Such an os hyoides is feen in tlie teltudo 

 gracca. But in the matamata (teftudo fimbriata, Gmcl.) 

 tlie body is very folid, bony,, and pyramidal, with the bafis 

 turned forwards. The anterior cornua, forming angles to- 

 wards the front, are articulated behind eacli angle termi- 

 nating the bafis ; while the poflerior, more flcnder, and bent 

 like an arc, are fixed near each other to the apex of the 

 pyramid. 



Ufually the os hyoides confifls merely of cartilage in the 

 faurians, as in molt other reptiles ; its parts are generally 

 flender, elongated, and confolidated with each other. Yet 

 it preferves in the crocodile that flattened (hield-like figure, 

 which we have defcribed it to poffefs in the chelonian order, 

 and which we (hall difcover alio in the batracians. There 

 are only two cornua, articulated nearly in the middle of the 

 fides of the cartilaginous plate. They feem formed of two 

 portions united together, but diftinguiflicd by a kind of 

 angle projecting poileriorly. 



In the common iguana (I. dtlicatifTima, lacerta iguana, 

 Linn.) the body may be confidered merely as the point of 

 union of the feven cornua compofing the os hyoides An 

 anterior one is continued under the tongue, without being 

 fixed to it. The fix others are behind. The two loweit 

 are the longeft ; they are contiguous, flightly curved, and 

 enter the goitre, without affording attachment to any muf- 

 cles or ligaments. The four others are true cornua of the 

 hyoid cartilage. Two pafs firft forwards, but quickly 

 bend backwards, and then upwards, to reach the occiput. 

 The others are bent backwards and upwards, fo as to re- 

 main nearly parallel to thefe. They are analogous, in their 

 form and ufe, to the correfpondmg parts in birds. The 

 cornua belonging to the goitre are found alfo in the fcinks, 

 agamcs, and dragons. In the dragon raye (draco lineatus) 

 their extremity is attached to the large bag forming the 

 goitre, and will draw it inwards, when the tongue paffes 

 out of the mouth. Thefe cornua are not found in the other 

 faurians. Sometimes there are only two hyoideal cornua, 

 as in the gecko fimbriatus. They are always perfeftly 

 analogous to thofe of birds. 



The OS hyoides of the cameleon has four ; of which two 

 are ftraight and dircdted obliquely forwards. The two 

 pofterior go behind the head. The body is prolonged to 

 nearly the anterior third of the tongue, when that organ is 

 in the ftate of repofe ; it is cylindrical .ind flender in the 

 whole of this part, which is between one and two inches 

 long. 



In the lizards and tupinambes, the number of cornua is 

 alfo four. The anterior are formed of two pieces, confo- 

 lidated, or moveable ©n each other, of which the firfl is 

 direfted forwards, while the fecond turns backwards, and 

 is curved towards the occiput. 



In the ophidians, with a tongue inclofed in a (heath, the 

 hyoid cartilage is compofed of two parallel threads, direfted 

 from before backwards, approximated to each other, fepa- 

 rated in their anterior half by the fheath of the tongue, and 

 in the reft of their extent by the two hyogloffi. The two 

 threads are united in front, nearly between the pofterior 

 extremities of the branches of the jaw, being bent into a 

 femicircle under the flicath of the tongue ; from the con- 

 vexity of their union a fhort point is continued under the 

 ilieath. In the other ophidians, as the amphifbsnae, &c, 



the 



