ROOM X.] 
NATURAL HISTORY. 
37 
ends, which has led to the idea that they walk both back¬ 
wards and forwards with the same facility,—hence their 
name. They are generally destitute of limbs ; but the 
genus Chirotes is peculiar for having two small rudi¬ 
mentary front legs. Most of them have teeth placed on 
the inner edges of the jaw, but the Trogonophides have 
them placed on the edge. They all live in ant-nests, and 
feed on those insects. 
The following Table exhibits the arrangement of this 
Class at one view; the numbers refer to the Cases. 
Class III. 
Reptilia. 
Sect. 1 . Squamata. 
Order I. Sauria. 
A. Leptoglossce. 
Fam. 1 . Monitor idee. 3. 
Psammosaurus 
Monitor 
Polydedalus 
Empagusia 
Hydrosaurus 
Fam. 2. Helodermidce. 
Heloderma 
Fam. 3. Teidce. 3. 
Teius 
Ctenodon 
Acrantus 
Ameiva 
Aporomera 
Cremidophorus 
Dicrodon 
Centropyx 
Ada 
Crocodilurus 
Custa 
‘“'Callopistes 
Fam 4. Lacertinidce. 3. 
Zootoca 
Lacerta 
Teira 
Eremias 
Acanthodactylus 
Scapteira 
Meroles 
Mesulina 
Calrita 
Algira 
Psammodromus 
Ophiops 
Calosaura 
Fam. 5. Zonuridcc. 3. 
a. Zonurus 
Tribolonotus 
Cicigna 
Tetradactylus 
Tachydromus 
Caitia 
Abronia 
b. Gerrhonotus 
Barisia 
Elgaria 
Pseudopus 
Ophisaurus 
Fam. 6*. Cercosauridee. 
Cercosaurus 
Fam. 7. ChirocolidcB. 
Heterodactylus 
Fam. 8 . Chamcesauridce . 
Chamaesaura. 5. 
Fam. 9. Chcilcidce. 
Chalcides 
Microdactylus 
Colobus 
Ecpleopus 
Pentadactylus 
Leposoma 
Fam. 10. Scinddee. 5. 
a. Scincus 
Sphenops 
b. Celestus 
Trachysaurus 
Tropidophorus 
Egernia 
Tiliqua 
Amphiglossus 
Euprepes 
Eumeces 
Leiolopisma 
Psammita 
Cyclodus 
Easia 
Gongylus 
wPlestrodon 
Adaria 
Herinea 
c. Riopa 
Lygosoma 
Chiamela 
Tetradactylus 
Seps 
Siaphos 
Heteromeles 
Ristella 
Hagria 
Tridactylus 
Ronia 
d. Ophiodes 
e. Anguis 
Ophiomorus 
Siguana 
Stenostoma 
Doriia 
