IGUANID^. 6 



shield-like disposition. An enlarged scale is usually present, repre- 

 senting the interparietal of other Lizards, and, through fusion with 

 adjacent scales, sometimes acquires a remarkably largo size. Fol- 

 lowing the example of previous authors, and for convenience, I have 

 used the term " occipital " for this shield, although it is not homo- 

 logous with that so-called ; but I have had to depart from this rule 

 in dealing with the genus Liolcemus, in which, owing to the greater 

 development of the parietals and the presence of a true occipital, 

 that terminology might have led to confusion. 



The habits of the numerous members of this family are as varied 

 as their physiognomy. All the forms which we have observed in the 

 Agamoids are repeated here, save the parachute-bearing Dragons, 

 which have no plcurodont analogues. On the other hand, such types 

 as tlie Aaoli's, with their digital expansions, and the semi-marine 

 algivorous Ainhh/ rhynchus, are unrepresented in the acrodonfc series. 

 However, this apparent parallelism between the Agamoid and Igua- 

 noid series of genera is very superficial, and there is, it appears to me, 

 not one form so exactly repeated in both as to deserve to be 

 united into the same genus, were the character of the dentition, on 

 vrhich the family distinction is based, not to be considered. 



The great majority of Iguanoids are insectivorous; Iguana, Bra- 

 chi/Iophus, Ainblyrhi/nchus, Conohphus, Phymaturus, Sauromalus, 

 BasiUscHS, are herbivoroixs ; and the Ctenosaura are reported to be 

 omnivorous. Some species of Scelopovus and Plirynosoma are at 

 present the only Iguanoids known to be ovoviviparous. 



With the exception of two genera occurring in Madagascar, and 

 one in the Friendly and Fiji Islands, the range of this family is 

 restricted to the Xew "World, 



Synopsis of the Genera. 



I. Femoral pores absent (or a few present, in the male sex only, in 

 the geuus Enyalioides). 



A. Digits more or less dilated or depi'essed, with smooth trans- 

 verse lamellce iuferiorly, the distal joint narrower, cylindrical 

 or compressed. 



1. Distal joint raised above the penultimate. 



Lateral teeth with subspheiical crowns; palatine and pterygoid 

 bones toothed 1. Chamaeleolis, p. 7. 



Lateral teeth tricuspid ; tail prehensile. 



2, Xiphocercus, p. 8. 



Lateral teeth tricuspid ; tail not prehensile. 



3. Anolis, p. n. 



2. Distal joint not raised. 



Digits scarcely dilated 4. Norops, p. 95. 



b2 



