240 PTGOPODID^. 



which is shared by Hdoderma ; (2) the reduction of the number 

 of bones in the mandible, in which respect they resemble the 

 Snakes. The vertical pupil, though of secondary importance, 

 deserves special notice, for it occurs in none of the other Skink-like 

 Lizards. 



Synopsis of the Genera. 



I. Parietal bones distinct ; head with large symmetrical shields. 



A. Praeanal pores. 



Scales keeled 1. Pygopns, p. 240. 



Scales smooth 2. Cryptodelma, p. 242. 



B. No praeanal pores. 



Scales smooth ; parietal plates large ; two rows of enlarged ventral 

 plates 3. Delma, p. 243. 



Scales bicarinate 4. Pletholax, p. 245. 



Scales smooth, subequal ; no parietal plates ; ear concealed. 



5. Aprasia, p. 245. 



II. Parietal bone single ; head covered with small scales. 



6. Lialis, p. 246. 



1. PYGOPUS. 



Sheltopusik (non Latr.), Oppel, Ordn. p. 40. 



Pygopus, Merr. Tent. Syst. Amph. p. 77 ; Fitzing. N. Class. Mept. 



p. 26 ; Wagl. Syst. Amph. p. 160 ; Wiegm. Herp. Mex. p. 11 ; 



Gray, Cat.y. 67. 

 Hysteropus, num. S^ Bibr. v. p. 826. 



Parietal bones distinct. Tongue slightly nicked at the tip, with 

 rows of large round papillae inferiorl)^ Ear exposed. Eudiments 

 of hind limbs externally. Head with large symmetrical plates. 

 Scales cycloid-hexagonal, imbricate, those on the back keeled, the 

 two median series on the belly, and the median series under the 

 tail transversely enlarged, hexagonal. Praeanal pores. 



Australia. 



1. Pygopus lepidopus. 



Pygopus lepidopodus, Gray, Cat. p. 67, 

 Pygopus squamiceps, Gray, I. c. p. 68, 

 Bipes lepidopodus, LacSp. Ann. Mus. iv. 1804, p. 209, pi. Iv. fig. 1 ; 



GuSrin, lean. R. A., Rept. pi. Ixi. fig. 1 ; JDuvem. R. A., Rept. 



pi. xxii. bis. fig. 2. 

 Sheltopusik nova;-bt)llandi8e, Oppel, I. c. 

 Pygopus lepidopus, Merr. Tent. p. 77 ; Giinth. Ann. Mag, N. H. (3) 



XX. 1867, p. 45. 

 Hysteropus novse-hollandiae, Dum. Sf Bibr. v. p. 828, pi. Iv. 

 Pygopus squamicep.o, Gray, Zool. Erebiu and Terror, Rept. pi. viii, 



fig, 3. 



