21. AMPHIBOLTJRUB. 381 



A nuchal crest ; tail a little compressed ; 



dorsal scales uniform 5. caudicinctus, p. 384. 



II. The hind limb stretched forwards does not reach bej'ond the 

 orbit. 



A. Prseanal and femoral pores 20 or more altogether, the latter 

 forming a long series on the whole length, or the proximal 

 two thirds, of the thighs. 



1. Ventral scales smooth. 



Dorsal scales uniform, lateral scales inter- 

 mixed with very small tubercles .... 6. decresii, p. 385. 



Dorsal and lateral scales uniform 7. pietus, p. 385. 



Dorsal scales heterogeneous 8. reticulatus, p. 386. 



2. Ventral scales keeled. 



Gular scales keeled ; body with longi- 

 tudinal series of angular black spots . 9. adelaidensis, p. 387. 



Gular scales smooth or very feebly keeled 10. puloherrimus, p. 388. 



Gular scales keeled ; upper surfaces uni- 

 form pale brown 11. pallidus, p. 388. 



B. Prseanal and femoral pores 22 or less altogether, the latter 

 extending only on the proximal half of the thighs. 



The adpressed hind limb reaches the 



tympanum or between the latter and 



the orbit ; no dorsal crest or serrated 



ridge 12. anguUfer, p. 389. 



The adpressed hind limb reaches the eye 



or between the latter and the tym- 

 panum ; a small vertebral crest or 



serrated ridge 13. muricatus, p. 390. 



The adpressed hind limb reaches the 



axilla or the shoulder ; no dorsal crest 



or ridge 14. barbatus, p. 391. 



1. AmpMbolurus maculatus. 



Grammatophora maculata, Gray, Cat. p. 253. 

 Uromastyx maculatus, Grap, Griff. A. K. ix., Syn. p. 62. 

 Grammatophora gaimardii, thim. 8f Bibr. p. 470. 

 Homalonotus gaimardii, Fitz. Syst. Mept, p. 83. 

 Grammatophora isolepis, Fischer, Arch. f. Nat. 1881, p. 232, pi. xii. 

 figs. 10-12. 



Habit slender. Head moderately large ; snout as long as the 

 diameter of the orbit, with angular canthus rostralis ; nostril a 

 little nearer the eye than the end of the snout, situated below the 

 canthus rostralis ; tympanum large, measuring a little more than 

 half the diameter of the orbit ; upper head-scales subequal, strongly 

 keeled, smallest on supraorbital region. Sides of neck rather 



