9. BASILISCFS. 107 



Corytliasolus, Kaup, Isis, 1828, p. 1147 ; Wieym. I. c. pp. 15, 'AQ ; 



Fitziny. I. c. ; Gray^ Cat. p. 192, and Ann. l^- Maq. N. II. (2) x. 



p. 43<J. 

 O^dicoryphus, WagJ. I. c. 

 Thjsanodactvlus, Gray, Cat. p. 193, and Ann. Si Maq. N. II. (2) x. 



p. 439. 

 Ptenosaura, Gray, Ann. Sf May. N. II. (2) x. p. 438. 

 Lopbo.saura, Gray, I. c. 

 Cristasaura, Gray, I. c. 



Craneo-saura, Gray, in Richards. Zoul. Herald, p. 148. 

 Paraloiua, Cope, Proc. Ac. Phi/ad. 1802, p. 181. 



Tympanum distiuct. Head, in the adult male, produced pos- 

 teriorly into a large cartilaginous lobe. Eody compressed, covered 

 M'ith imbricate small scales ; male with a dorsal crest. No gular 

 pouch ; a transverse gular fold. Toes bordered on the outer side by 

 a much developed dermal lobe. No femoral pores. Tail long, 

 strongly compressed, crested in the male. Lateral teeth tricuspid ; 

 pterygoid teeth. Clavicle loop-shaped proximally. No sternal 

 fontancile. No abdominal ribs. 

 Troijical America. 



All species agree in the following characters : — Head largest in 

 the male, with swollen cheeks and a large crest on the back of the 

 head ; this crest hardly developed in the females and not at all in 

 the young. Snout pointed ; eye-opening and tympanum large ; 

 upper head-scales small, irregular, keeled ; labials large ; a row of 

 large chin-shields on each side ; gular scales smooth. Dorsal scales 

 smaller than ventrals, imbricate, more or less distinctly keeled. 

 Limbs long, covered above with keeled scales larger than the 

 ventrals ; the adpressed hind limb reaches the tip of the snout, or a 

 little beyond. Caudal scales keeled, much enlarged inferiorly. 



Si/7topsis of the Sjiecies. 



I. Males with very high, rayed, dorsal and caudal crests ; ventral 



scales perfectly smooth. 



Head-crest undivided, rising from an imagi- 

 nary line connecting the upper borders of 

 the ear-openings 1. americanus, p. 108. 



Head-crest bisected, rising on a line with 



the posterior borders of the orbits 2. phmiifrons, p. 108. 



II. Males with a low, not rayed, caudal crest. 



Dorsal crest rayed ; head-crest rising from 



the occiput ; ventral scales keeled* .... 3. vitiatus, p. 109. 

 Dorsal crest not rayed ; head-crest rising on 



a line with the posterior borders of tho 



orbits ; ventral scales smooth 4. yaleritas, p. llO. 



* The keel sometimes very nadistinct in adult males. 



