400 AGAMIDiB. 



The chief difference between this species and the following appears 

 to be the greater number of lateral or molar teeth (eighteen on each 

 side in each jaw) and the presence of only six or seven shields along 

 each side of the throat. In other respects, both forms are very 

 similar. 



Coohinchina. 



7. Physi^athus mentager. 



Dilophyrus mentager, Gunth. Proc. Zool. Soc. 1861, p. 188. 

 Physignathus mentager, OiXnth. Mept. B. Ind. p. 153, pi. xv. 



Head moderately elongate ; snout slightly longer than the diameter 

 of the orbit ; canthus rostralis well marked ; nostril nearer the end 

 of the snout than the orbit ; tympanum one third the diameter of 

 the orbit ; upper head-scales minute, granular, keeled, a little 

 enlarged on canthus rostralis and supraorbital border. Eleven 

 molar teeth on each side of the upper jaw, and twelve in the lower. 

 Gular scales, large juxtaposed granules, unequal on the sides ; three 

 or four of the posterior lateral ones largest and conical ; a series of 

 eleven large shields on each side, parallel with the infralabials. 

 Nuchal crest composed of lanceolate spines, which are very long in 

 the adult male, short in the half-grown, supported by a fold of the 

 skin covered vnth granular scales ; dorsal crest formed of similar 

 spines, a little lowered above the shoulders, but continuous with the 

 nuchal. Dorsal scales equal, minute, granular, feebly keeled ; 

 ventral scales larger, imbricate, smooth. Limbs long, covered with 

 minute, slightly imbricate, keeled scales ; the adpressed hind limb 

 reaches between the orbit and the tip of the snout. Five pores 

 under the basal part of each thigh. Tail strongly compressed, about 

 twice and a half the length of head and body, crested above, the 

 crest as much developed as, but not continuous with, the dorsal ; 

 lower caudal scales enlarged and strongly keeled. Green, a little 

 Ugbter inferiorly; rather indistinct, narrow oblique lighter bands 

 down each side of the body ; enlarged gular shields and tubercles 

 whitish ; tail with dark-brown aimuli. 



The largest specimen measures 23 centim. from snout to vent, 

 and the tail measures 55 centim. The following measurements are 

 taken from the smaller specimen ;■ — 



Total length 550 miUim. 



Head 38 „ 



Width of head 27 ,. 



Body 112 „ 



Fore limb 70 „ 



Hind limb 130 „ 



Tail 400 „ 



Siam. 



... Adull _ , 



b. Hgr. (J . Pachebone. M. Mouhot [C 



a. Adult cJ , stutied. Chartaboum. M. Mculiot [C.l. (Type.) 



