18 IGXJANID^. 



VI. Tail strongly compressed ; dorsal scales much larger than the 

 laterals. 



Dorsal and ventral scales rhomboidal, imbri- 

 cate, keeled 63. pulchellus, p. 67. 



VII. Tail cylindrical or feebly compressed ; dorsal scales larger 

 than the laterals whenever the digital expansions are distinctly 

 developed ; dorsal and lateral scales equal or nearly equal in a 

 few species in which the third phalanx of tbe fourth toe is not 

 distinctly wider than the basal. 



A. Dorsal scales as large as or larger than the ventrals, 



1. Head (to occiput) longer than the tibia. 



a. Dorsal scales not larger than the ventrals. 



Dorsal and ventral scales large ; occipital en- [p. 68. 



larged 64. semilineatus. 



Scales smooth ; occipital not larger than the 



surrounding scales 91. oxylophus, p. 84. 



h. Dorsal scales larger than the ventrals. 



a. Scales on upper surface of snout smooth. 



Dorsal and ventral scales keeled Qo. sjiectrum, p. 69. 



Dorsal and ventral scales smooth 67. Uonotus, p. 70. 



/3. Scales on upper surface of snout keeled or striated. 



Dorsal scales feebly keeled or striated QQ. cyanophurus. 



Dorsal scales strongly keeled, in about ten [p. 69. 



longitudinal series 86. humilis, p. 82. 



Doi'sal scales strongly keeled, in seven series . 87. quac/gulas, p. 83. 



2. Head not, or scarcely, longer than the tibia ; dorsal and 



ventral scales sharply keeled. 



Dorsal scales larger than ventrals ; tibia as long [p. 83. 



as the head 88. trojndonotus, 



Dorsal scales larger than ventrals ; tibia 



shorter than the head 89. uniformis, p. 84. 



Dorsal scales not larger than ventrals 90. mctaUicus, p. 84. 



B. Dorsal scales smaller than ventrals \ 



1. The length of the tibia is less than the distance between 

 the end of the snout and the ear. 



a. Ventral scales smooth. 



Head elongate 68. alutaceus, p. 71. 



b. Ventral scales keeled. 



a. Occipital considerably longer than the greatest dia- 

 meter of the ear-opening. 



^ In a few species yery slightly. 



