630 Bulletin American Museum of Natural History [Vol. XL VI 



The species of Scaphiopus in Lower California may be distinguished 

 as follows: 



Snout sharply truncate in profile S. hammondii. 



Snout rounded in profile S. couchii. 



The reptiles of Lower California include lizards, snakes and a single 

 species of non-marine turtle. The lizards represent nine families: 

 Gekkonidse, Eublepharidse, Iguanidae, Anguidse, Anniellidse, Xantusiidse, 

 Teiidse, Scincidse, and Amphisbsenidse. The snakes represent four 

 families: Leptotyphlopidse, Boidse, Colubridse and Viperidse. These 

 families may be distinguished as follows: 



1. Both pairs of limbs present 2. 



Only one pair of limbs, or none 8. 



2. Eyelids absent 3. 



Eyelids developed 4. 



3. Top of head covered with small granular scales; tips of digits dilated with a 



pair of plates beneath Gekkonidse. 



(a single genus in Lower California, Phyolldactylus) . 



Top of head with large plates; tips of digits not dilated Xantusiidse. 



(a single genus in Lower California, Xantusia) . 



4. Top of head covered with very small granular scales, skin free from skull, pupil 



vertical Eublepharidee. 



(a single genus in Lower California, Coleonyx) 

 Top of head covered with scales larger than those of the back, skin not free from 

 skull 5. 



5. A series of femoral pores 6. 



No femoral pores 7. 



6. Ventral scales in regular transverse and longitudinal series Teiidse. 



(see key below). 



Ventral scales not in regular series, more numerous Iguanidse. 



(see key below). 



7. Dorsal scales smooth, laterals and ventrals not much different Scincidse. 



(a single genus in Lower California, Plestiodon). 

 Dorsal scales keeled, lateral scales smaller than dorsals or ventrals, a strong 



lateral fold Anguidse. 



(a single genus in Lower California, Gerrhonotus) . 



8. A pair of anterior limbs, no posterior pair Amphisbsenidse. 



(a single genus in Lower California, Bipes, forming a distinct sub- 

 family (Bipedinse) of this otherwise limbless family). 

 No anterior or posterior limbs 9. 



9. Scales of the lower surface not enlarged . 10. 



Ventral scales enlarged 11. 



10 Eyes present, external Anniellidse. 



(a single genus in Lower California, Anniella). 

 Eyes absent externally, visible as a black dot beneath the scales which cover 



them Leptotyphlopidse. 



(a single genus in Lower California, Siagonodon). 



