GERRHOSAUIUD.E. 



119 



Fam. 17. GERRHOSAURID^. 



Scincidse, part., Anguidie, part., Gray, Ann. Fhil. (2) x. 1825. 



Opliisaiiroidt'rt, part., Fitzim/er, Neue Clasaif. Rept. 182(5. 



AiitarclioglossiC, part., Wdf/ler, Si/d. Amph. 1830. 



I'lyclidpleuri. jmrl., Wief/mann, IL rp. Me.v. 1834. 



Chalcidieus Ptychopleures, part., Dunieril <^- Bihron, Erp. Gen. v. 



1S39. 

 Zouurida?, part.. Gray, Cat. Liz. 1845. 



Zumirida), part.. Cope, Proc. Am. A^soc. Adv. Sc. xix. 1871. 

 GerrhosauridiB, Boulenger, Ann. iSf Blag. N. II. (5) xiv. 1884. 



Tongue moderately elongate, bifid posteriorly, free and very 

 feebly nicked anteriorly, covered with imbricate scale-like papillae 

 or obli(iue plica; converging anteriorly towards the median line. 



Dentition pleurodont ; teeth closely set, with long cylindrical 

 shafts, hollow at the base, with conical or bicuspid crowns. Ptery- 

 goid teeth often present. 



tSkull in every respect similar to that of the Lacertidce, with 

 dermal ossification roofing over the supratemporal fossae. Limbs 

 well developed or rudimentary. Clavicle dilated and loop-shaped 

 proximally ; iuterclavicle cruciform. Tail long and fragile. 



Head with symmetrical shields. iJody with squarish or rhom- 

 boidal imbricate scales, which often form regular longitudinal and 

 transverse series ; it is besides protected by osteodermal plates, un- 

 derlying the scales, which show a system of longitudinal tubules 

 intersecting a transverse one, as in the Scincidce; this structure 

 usually more distinct on the ventral plates than on the thicker and 

 rougher dorsal ones. A lateral fold, with granular scales, similar 

 to that of Gerrlionotus, is present in all genera except Traclie- 

 loj^tychus, which in its scaHng more resembles the Seines. 



Femoral pores constantly present. Eyelids well developed. Tym- 

 panum distinct. 



This family is exactly intermediate between the Lacertidce (single 

 prasmaxillary, femoral pores) and the Schicidce (presence and struc- 

 ture of the dermal bony plates). It is strictly African, its head- 

 quarters being South Africa and Madagascar, and extending north- 

 wards to the southern limit of the Sahara. 



Synopsis of the Genera. 



I. Nostril pierced between two nasals and the first labial ; ventral 

 plates forming straight transverse series. 



Tongue nearly entirely covered with imbricate scale-like papillae ; 

 praefrontals and frontoparietals present ; lower eyelid scaly. 



1. Gerrhosaums, p. 120. 



Tongue nearly entirely covered with oblique plicse ; no praefrontals ; 

 frontoparietals present ; lower eyelid scaly ; limbs short or 

 rudimentary 2. Tetradactylus, p. 124. 



