20. LIOCErHALUS. 161 



Pristinotus, Gravenh. N. Acta Ac. Leop. -Carol, xviii. 1838, ii. p. 738, 



Scelotrema, Tschudi, Faun. Per., Herp. p. 27*. 



Ophrvoessoides, A. Bum. Cat. Mcth. liept. p. G6, and Arch. Mus. viii. 



p. 530. 

 Brachysaurus, Hallotv. Proc. Ac. Philad. 1856, p. 232. 



Tympanum distinct. Body more or less compressed ; a more or 

 less developed dorsal crest ; dorsal scales uniform, imbricate, keeled. 

 Upper head-scales small or enlarged, smooth or keeled ; no large 

 occipital. No transverse gular fold ; no gular sac. Digits com- 

 pressed, with keeled lamellLC interiorly. No femoral or pra^anal 

 pores. Tail long, more or less compressed and crested. Lateral 

 teeth tricuspid ; pterygoids usually toothed. A sternal fontanelle. 

 Abdominal ribs. 



West Indies ; South America. 



Synojysis of the Species. 



I. Parietal plates distinct ; a series of band-like transverse supra- 

 oculars. 



A. Parietal plates longitudinally divided ; nasal in contact with 

 the rostral. 



1. Ventral scales smooth. 



a. Outer parietals not twice as large as inner. 



a. Caudal crest not higher than dorsal. 



Side of neck granular ; adpressed hind 



limb not reaching the eye 1. schreibersii, p. 162. 



Side of neck, for a short distance posterior 

 to the ear-opening, granular ; adpressed 

 hind-limb quite or nearly reaching end 

 of snout 2. macropus, p. 163. 



Side of neck entirely covered with imbri- 

 cate, pointed, keeled scales ; adpressed 

 hind limb not reaching beyond the eye 3. vittatus, p. 163. 



j3. Caudal crest higher than dorsal. 



Keels of the dorsal scales unusually strong 4. 7nelanoc7iIorus,\).lG4i. 



Upper head-scales striated ; a black band 

 on the side of the head, passing through 

 the eye 5. personatus, p. 164. 



Upjjcr head-scales smooth, except the su- 

 praoculars ; dorsal scales larger than 

 ventrals 0. eremitus, p. 165. 



* The smuU poucli bel weoii the tail and tlie base of the liind limb, noticed by 

 Tschudi, i.s more or less disiiiiol in specimens of L. acukafus, trachyccphalus, 

 and (/uenthcri ; it is most developed in L. ornatus. 



VOL. II. M 



