120 GERRHOSAURIDA. 
Tongue nearly entirely covered with imbricate scale-like papille; 
no prefrontals ; frontoparietals present or absent; lower eyelid 
with a large transparent disk .. 3. Cordylosaurus, p. 126. 
II. Nostril pierced between two nasals, the rostral, and the first 
labial; ventrals not forming straight transverse series. 
A lateral fold along the body ; no frontoparietals. 
4, Zonosaurus, p. 127. 
No lateral fold on the body; frontoparietals present. 
5. Tracheloptychus, p. 129. 
1. GERRHOSAURUS. 
Gerrhosaurus, Wiegm. Isis, 1828, p. 878, and Herp. Mex. p. 11; 
Wagl. Syst. Amph. p. 158; Gray, Cat. Liz. p. 52, and Proc, Zool. 
Soc. 1865, p. 642. 
Cicigna, part., Gray, Griff. A. K. ix. Syn. p. 63. 
Pleurotuchus, Smith, Mag. Zool. Bot. i. 1837, p. 142. 
Gerrhosaurus, part., Dum. § Bibr. v. p. 868. 
Nostril pierced between the first labial and two nasals; preefrontal 
and frontoparietal shields present. Lower eyelid scaly. A strong 
lateral fold. Dorsal and ventral scales forming straight longitudinal 
and transverse series. Subdigital scales smooth or tubercular. 
Tongue entirely covered with rhomboidal papille. 
Tropical and South Africa. 
Synopsis of the Species. 
I. Ventral shields in 14 or 16 longitudinal 
series ; tympanic shield large, cres- 
centic; dorsal shields pluricarinate . 1. validus, p. 121. 
II. Ventral shields in § longitudinal series ; tympanic shield narrow; 
dorsal scales unicarinate. 
Prefrontals in contact, forming a long su- 
ture; dorsal shields in 18 or 20 longi- 
tudinal series)... gvwe-e ous putes eons 2. major, p. 121. 
Prefrontals in contact, forming a long 
suture; dorsal shields in 24 to 28 
longitudinal series, all keeled ........ 3. nigrolineatus, p. 122. 
Prefrontals separated, the frontonasal 
touching the frontal; dorsal shields 
in 20 to 24 longitudinal series, the 
laterals not distinctly keeled ........ 4, flavigularis, p. 122. 
III. Ventral shields in 10 longitudinal 
series; tympanic shield large, cres- 
centic; dorsal shields unicarinate .. 5. typicus, p. 123. 
