44. PETROSAURUS. 45. CALLISATJRUS. 205 



44. PETROSAURUS. 



Tympanum distinct. Body depressed ; no dorsal crest ; dorsal 

 scales small, granular, smooth, uniform. Upper head-scales a little 

 enlarged, occipital very large. Two strong transverse gular folds 

 without denticulatiou ; no gular sac. Digits with keeled lamellae 

 interiorly. A long series of femoral pores. Tail long, feebly de- 

 pressed. Lateral teeth tricuspid ; no pterygoid teeth. A sternal 

 fontanelle. No abdominal ribs. 



Lower Calfornia. 



1. Petrosaurus thalassinus. 



Uta thalassina, Cope, Proc. Ac. Philad. 1803, p. 104. 



Head rather small, snout narrowed ; nostril large, superior, 

 equally distant from the orbit and the end of the snout ; ear- 

 opening large, oval, with a denticulated lobe of skin anteriorly ; 

 head-scales smooth ; a single scale in the middle between the 

 orbits ; three longitudinal series of supraocular scales, surrounded 

 by granules ; occipital nearly as large as the tympanum ; a large 

 infraorbital ; upper labials seven or eight, \Qry low ; lower labials 

 larger. Throat granular, with two strong transverse folds, the 

 anterior forming a small pouch on each side ; a third, less marked, 

 anterior fold ; sides of neck strongly plicate. Dorsal and lateral 

 scales uniform small, convex, smooth granules ; ventrals larger, flat, 

 squarish or hexagonal. Limbs moderate, with larger keeled scales; 

 the adpressed hind limb reaches the tympanum ; digits strong, com- 

 pressed. Sixteen or seventeen femoral pores on each side. Tail 

 slightly depressed, slender, covered with rings of small, squarish, 

 obliquely keeled scales ; its length once and a half that of head 

 and body. Olive above, fore limbs and anterior part of back with 

 a fine black network ; back with transverse series of pale greenish 

 spots alternating with dark cross bands, of which the three anterior 

 are of an intense black, bordered with pale greenish posteriorly ; 

 tail with darker and lighter cross bars ; lower surfaces greenish 

 white, throat blackish. 



milUm. milliin. 



Total length 311 Fore limb 52 



Head 30 Hind limb 81 



Width of head .... 23 Tail 185 



Body 96 



Lower California. 

 a. (S . Cape St. Lucas. Smithsonian Institution [P.]. 



45. CALLISAURUS. 



Callisaurus, Blainv. Nouv. Ann. Mus. iv. 183.5, p. 28G ; Dum. ^- Bibr. 

 iv. p. 324; Gray, Cat. Liz. p. 226 ; Bocourt, Miss. Sc. Mex., Rept. 

 p. 158. 



