

IGUAN1D.E. 



lit 



etate, that p to the time when they wrote they knew of no 

 to which ohesrven had detected a linear pupil, though it i* 



i that *ome are nocturnal With the exception of some genera, 

 Ols.l|-| awl Plkrwute^ktlui in particular, in which the tympanum 

 Is oat apparent, all the Ignanian* have an auditory canal, more or 

 ! enlarged at iU external orifice on a level with the surface of 

 the head; ometime*. a* in eome epeoie* of Aftma, it 1* only a simple 

 lit, the entrance of which U protected by some pointed and as it 

 were *piay em la* The MOM of -tilling does not seem to be much 

 developed hi the thnrhmr generally, but in the family under con-idc- 

 ration it appear* to be at a very low rate, for there is no anfractuonity 

 la the aUvemn*; the external orifioM of the nostrils have but little 

 humidity, and are very small. They are situated generally noar th* 

 extremity of th* mnnle, and approach each other above ; they open 

 within the mouth by a simple slit to which tho tongue may be 

 applied, and *eem principally, if not entirely, destined to aid in 



The tongue i* in general abort, large, and mobile at it* extremity ; 

 but it is not deeply divided at its end, which is free. The base is 

 not retracted into a sheath, and this i* a character which distinguishes 

 it in particular from that of the Varanians and Chameleons. Wagler 

 ha* employed the term Padtygtoui to denote this disposition. The 

 organ is always humid, and covered with a glutinous secretion : its 

 ppill- which vary in form, being in some instances conical, and in 

 others scaly, or laid like tiles (entuiloes), in a direction from the front 

 backwards, appear to be destined for the perception of sapid sub- 

 stance* ; but it* principal office seems to be to direct the movement 

 of the food submitted to the action of the teeth, and to assist in 

 deglutition. The o* hyoides, to which it is fastened, presents import- 

 ant modification* in different genera, IU horns are much prolonged 

 in some specie*, and serve to support the dewlap, or longitudinal fold 

 of the integument* under the neck and jaw, in Sitana, Batilitcut, 

 Dram, Ac., and especially in Anolit, as particularly noticed and 

 demonstrated by Mr. T. Bell 



The organ* of digestion present nothing very remarkable in this 

 family. The stomach seems to be a continuation of the oesophagus, 

 but the fibres and wrinkles are most often in another direction. There 

 i* no true cardia. The ventricuhia, properly so called, is often conical, 

 and the pylorus is not distinguishable except by a slight narrowing, 

 which i* rather elongated in Stcllio, Iguana, &c. In Polychrui, 

 OaVnrfft, and Lyrioctphalut, the pylorus is but little marked, on account 

 of it* shortness and the thinness of its paricte*. The intestines vary 

 in length. In species which have the tail very long, as the Iguanas, 

 the extent of the digestive tube U not much more than one-third of 

 the total length of the spinal column. There is no apparent distinction, 

 in *ome canes, evident between the small and large intestines, so that 

 there U often no caecum, a* in Cordyliu, Agama, and Sitana ; whilst 

 OB th* contrary in Iguana, Galeola, and Lyriocephalia, there U a 

 true enl-deMC at the termination of the small intestine where it 

 opens into the greater canal The pancreas U voluminous in Iguana, 

 /sriwtu, *nd Lyriocrphalui. The form and situation of the spleen 

 vary. It i* most frequently placed at the middle of the mesentery, 

 under the stomach ; aometime* on the right, as in Iguana ; sometimes 

 on the K-ft, or at the middle of the lower portion of the stomach, as 

 I* obMrvabl* in the greatest number. 



The organ* of circulation and respiration present no remarkable 

 illflhmn i from thoM of other Saurian*, and the same may be said of 

 UM organ* of generation. 



The integument* present various modifications. We have the 

 polyedrou* tubercles of Orammalophorut ; the spines of the neck in 

 Agama ; thoM of the tail in Dorypkorui, Strobilurui, Stenocercuf, 

 I'nmatlLr, and Trochycyelui ; the carinated scale* of Ophryoetia, 

 Lmuatflni, Tropidogatter, and Ecpkymota ; the cutaneous expansions 

 of the diffcrmt region* of the dorsal and caudal crest* in the greater 

 number of genera, but Mpecially in Iguana, Itliurui, and Banlitcvt ; 

 thoee of the nape on the occiput in Voryihophane* and BatUitcui ; of 

 the flank* in Draco and CaUuaurut and of the neck, under the form 

 of a dewUp, in Silana, Draco, and Iguana ; or in the lateral part* in 

 front of th* shoulders, as m (.'hlamyilotaurut. The pores, whether of 

 th* thigh*, aometlmM in a simple line, somtimea in two longitudinal 

 and parallel rows, or in front of the anus, are employed by Messrs. 

 Domcnl and Bibron in the clawfication of genera in their synoptical 

 table. The to** are in general elongated and terminated by crooked 

 nail*; Anolit alonepreeente a peculiar dilatation under the penulti- 

 mate phalange*. The shorter the toe* and the nails, tho less nimble 

 th* animal 



Mesan. Dnmeril and Bibron state that in their anatomical researches 

 they hav* found the ventriculu* of mauy species filled with debris of 

 vegetables, nob. M flower*, leave*, and seeds, in considerable quantity, 

 which led them to the conclusion that many are herbivorous ; but 

 they remark that thu i* scarcely in accordance with the form of the 

 t*eth, none of which have tubercular crowns, nor composed of 

 apparent enamel and oanraui cement. It should however be remem 

 bend that the teeth of mott of the species are by no means ill 

 adapted for cropping vegetable enbstance*. The family are generally 

 nimbi*. Th* ooinpremrj and lengthened tail of many opecies is most 

 ttacful M an inurnment of progreMion when swimming across the 

 -1 Mvanoahs, and their crooked nail lasaist them in climbing 



tree* and pursuing the smaller animals on which they occasionally 



The Iguanidte are all inhabitant* of warm climate*. Only one 

 belong* to Europe, the Common Stellio, which is found also in Africa 

 and Asia. Several inhabit Australia. 



The genus Iguana it the type of this family. This name was given 

 by Laurenti to a genus of Saurian*, in which he included various 

 forms, such a* Agama, Lopkyrui, Calotet, Ac. Daudin separated from 

 this heterogeneous collection Agama, Draw, and Barilucut ; and 

 Wagler, striking out the word Iguana from hi* nomenclature, divided 

 the genus /guana as left by Daudin into the genera Jlyiailoi-hui, 

 Metupoceroi, and A mblyrhynehui. Messrs. Dumeril and Bibron restore 

 the name. The genus Iguana, a* adopted by them, includes Hyi*i- 

 lophui and AmUyrliynckui of Wagler, and i* thu* characterised : 



A very large thin dewlap (fanon) under the neck. Cephalic 

 polygonal, unequal in diameter, fiat or carinated. A double > 

 small palatal teeth. Maxillary teeth with their edges finely dentilated. 

 A crest on the back and tail. Toes long and unequal A single row 

 of femoral pore*. Toil very long, slender, compressed, covered with 

 small equal imbricated carinated scales. 



Common Iguana (Ignana ttibrrntlatn). 



They give the following description of the genus an thus modified : 

 The species composing this generic group are principally remarkable 

 for the cutaneous prolongation which constitutes over the whole 

 extent of the lower port of the head and neck a very deep and very 

 thin dewlap or pouch, tho free border of which describes a cum .1 

 line, and is dentilated at the part nearest the chin. The xkiu is 

 irregularly folded on the sides of this dewlap, behind which there is 

 another transversal fold which is obliquely prolonged upon 

 shoulder. There are also cuticular folds on the lateral regions of tho 

 neck and trunk. The head of the Iguanas is moderately Ion 

 has the form of a pyramid with four faces. The neck is slightly 

 compressed. The upper port of the body U convex and rounded, th 

 under part flattened. Tho limbs are long. The toes unequal, MM-! 

 sometimes denticulated on their edges ; the five toes of the pot>>i ioi- 

 feet are graduated ; the third and the fourth of the hand are equal in 

 length. The tail, which is very long and very slender, is flattened 

 slightly from right to left from its origin. The top and sides 

 head arc protected by polygonal scales varying in size, among which 

 some are convex, some flat, some carinated, and some even strongly 

 tuberculous. The subocular regions however are only furnished with 

 unall angular roundish scales with a slightly convex surface. It is 

 worthy of remark that the part of the skull which is situated between 

 the orbit* is protected by two longitudinal series of large angular 

 plates, whilst in Metopocerot and Cycluriu this same part of the 

 cranium is paved with small polygonal scales. A row of .- 

 angular, oblong, and often carinated scales adheres to the lower edge 

 of the orbital circle. The lips are furninhcd with large scaly | 

 whii-h are ordinarily quadrangular. There is also on each branch of 

 the lower jaw a row of large Beaten, tho lost of w ich is enormous in 

 some COUCH, presenting a diameter the quadruple of that of the others. 

 The scales which cover the upper part of the neck and tin; body r 

 slightly imbricated. Thy nro small, square, or lozenge* I' 



