REPTILES. 



Icrior btiiifT concealctl by tlie followinj^' piece. The lafl, or 

 fxlrcme portion, has all its tiirce rings vihbk' ; .Tiid the or- 

 gan coiifills, externally, of this piece, and the fu-d rings of 

 all the others. The two lall rings of each piece, included 

 in the two firft of the fucceeding, retain it in its place ; 

 but, as the diameter of the former is lefs than that of the 

 latter, each piece is quite loofe, and plays freely about that 

 which it envelops. None, except the iirll, is united to the 

 flcin of the animal, or connefted by any mufcle, nerve, or 

 veflel ; it is, therefore, merely an exterior covering, moved, 

 as any foreign body would be, when the end of the tail is 

 agitated. 



The different pieces of the organ arc formed fuccefTivcly 

 on the (Ivin of the tail, reccivmg from it the materials necef- 

 fary for its developcment, and adhering to it until its 

 growth IS complete. A fecond jiiece, entirely fimilar to the 

 firft, is formed under it, and detacl;es it from the end of the 

 tail. It is pufhed backwards, leaving between its edge and 

 the flcin of the tail an interval occupied by the full ring of 

 the new piece, of which the fecond and third rings are co- 

 vered by the iirlt piece. The latter is retained by this con- 

 nexion, but plays freely round the firil piece. A third 

 piece is formed under the fecond, as that was under the firll ; 

 pulhing the fecond backwards, but retaining it by its two 

 pofterior rings being included in the cavity of the fecond 

 piece. 



If the vertebr.-e of the tail continue of uniform diameter, 

 all the pieces will be of the fame fize, and the rattle, confe- 

 qnently, is of one breadth throughout. On the contrary, 

 it the vertebrse grow while the rattle is being formed, the 

 pieces increafe in fize, and thus the rattle tapers to its 

 end. 



It is evident, from the preceding defcription, that one 

 piece only can he formed at each partial moulting of the 

 end of the tail ; but as we do not know whether thefe 

 raoultings coincide with the general fcparation of the epi- 

 dermis from the body, nor the periods ot their recurrence, 

 the number of pieces not only affords no proof of fpecific 

 differences, but alfo indicates nothing about the age of the 

 animal. Lacepede, Hift. Nat. des Serpens, i2mo. t. 2. 

 p. 217. 



Horns, life, of other Serp:nts and Reptiles. — I'he Egyptian 

 ceralles is fo named, from its two movcLble, pyramidal, four- 

 fided, curved horns, about two lines in length, placed above 

 the eyes. They confitt of fncceflive ftrata, of which the 

 exterior f::parates like an epidermis, exhibiting always four 

 grooved fides. The exterior ilratum feparates thus with 

 the animal's flcin, like the epidermis of the fcales, which 

 this refembles entirely in its texture. Lacepede, ubi fupra, 

 t. I. p. 256. 



[r. the batracian order, the horned frog has a conical 

 horny elevation above each eye ; and the rana margaritifera 

 a peculiar hard crifta on each fide of the head. 



The cecilia ibiara has two fmall tentacula or cirri, fcarcely 

 vifible near the noftrils ; and the ferpcnt, which Lac&p^de 

 lias named erpeton tentacule (Annales du Mufeum, t. 2. 

 p. 280.) has two fleihy appendages, covered with fcales, ex- 

 tending from the end of the fnout horizontally forwards. 

 Is there any probability that thefe parts in the cecilia and 

 erpeton are organs of touch ? 



Facial Pouches of Serpents. — A fmall bag has been ob- 

 ferved in the rattleinake, m fixteen colubres, and three bose, 

 between the eye and the nolb-il ; it has a rounded form, 

 refting in a hollow of the bone, in fhape not unlike the or- 

 bit. A fmall orifice behind the noftril leads to it. Thefe 

 bags, which are lined with cuticle, have their covering call 

 with the reft of the animal's Ikin. The cavities in queftion 



were noticed in the rattlefnake by Tyfoii, Pliil, Trauf. 

 V. 13. p. 26 ; and they have been fincc defcribed and deli- 

 neated by Dr. Riiflel and fir Everaid Hume. (Phil. Tranf. 

 1804, p. 70. j The latter anatomift difcovered nothing like 

 a fecretory apparatus about them, nor any thing that could 

 lead to ccnijedturcs concerning their oflice. They appear 

 moft analogous, in fituation and flrudure, to the fmall bagb 

 of the deer and antelope, called by the French larmiers. 



We conclude our review of the flruifture and phyfiology 

 of reptiles with the fummary of the principal differences 

 between their economy and that of the warm-blooded 

 clafFes, which terminates the excellent " Specimen" of Blu- 

 menbach. 



" Et calidis quldeni aninialibus a prima inde formationis 

 origine ad ultiniuni ufquc vitx haliluwi phlogiilicus ut hodie 

 audit proceffus. Mamnialium fcetui placentas adininiculo, 

 quae foetale phlogifton materno elcniento igiieo commutat. 

 Pullo incubato porofic teft;t et albuininis ope, quae itidem 

 igneo pabulo aditum, phlogifto vero fiiperfiuo exitum conce- 

 dunt. In lucem vero editis turn mammalibus tum avibus, 

 perpetuo et alterno refpirationis rhythmo. 



" Interims porro huic phlogiflico proceffui cum reliquis 

 fundionum clafiibus nexus, maxime cum iis fyftematis ner- 

 vofi, ut hiberni mammalium veterni, pha;nomcnis quae fupra 

 tetigimus, verifimillimus redditur. 



" Ipfius porro nervofi fyftematis fumma cum reliquis 

 fundfionibus confpiratio, praefertim ope rcaftionis fenforii 

 ab ea encephali portione pendente, qua; prxter originis ner- 

 vorum fuper eft. 



" Ex his omnibus fummus quidem funftionum vigor, mo- 

 bilitas fumma, hinc corpus vivum infinitis modis innumero- 

 rum, et multifariorum ftimulorum iinpetui et impreffionibus 

 fufcipiendis aptum : hinc pras ceteris omnibus fumma homi- 

 nis prsrogativa, in quo, uti, pridem obfervante Hippocrate, 

 confluxio una, confpiratio una, confentientia omnia, ita et 

 omnium maximus et innumerus cum univerfa rcliqua cum 

 ambiente creatione nexus. 



" Longe alia e contrario amphibiorum natura. 

 " Phlogifticus proceiTus noftratibus perexiguus lentif- 

 fimus. 



" Debilis etiam in omnibus amphibiis fanguinis in ence- 

 phali funftiones influxus. 



" Exigua porro parvi fenforii in craflas nervas reaiftio. 

 "Minor hinc in univerfum confenfus ; minus unius fuiic- 

 tionis in alteram imperium. 



" Minor hinc totius macliinas animate mobilitas. 

 " Verum eo major ab altera parte fimplicioris iftius vit;e 

 tenacitas, quod parte una affefta, fyftemate uno aiHicto, non 

 tarn facile reliqua in confenfum trahantur. 



" In univerfum ergo vita magis vegetativa, reprodudtioni — 

 ut per utrumque organicum naturas regnuin conftat — longe 

 magis opportuna, quam quae altioris ordinis facultatibus, 

 confenfibus, et complicatas confpirationis fubtilitate viget." 



Anatomical Defcription of the Proteus Aiiguinus, and Siren 



Lacertina See Cuvier, Recherches fur qiielques Reptiles 



douteux, infertcd in Humboldt's Recueil d'Obfervations 

 de Zoologie et d'Anatomie comparee faitcs dans fon 

 Voyage, t. i. 



By the word amphibious, applied to animals, naturalills 

 have meant to defignate the power of living, and particularly 

 of breathing, equally well in water and in air. In this fenfe 

 it cannot be applied, vrith propriety, to any of the animals 

 who have received the appellation from the ancients, and 

 moft modern naturalifts. Without fpeaking of the otterS 

 and hippopotami, which are true aerial quadrupeds, vifitig. 

 the water merely ia fearch of food, the feals and cetaceou" 

 5 1' 2 auiraalsy 



