CROCODILIANS, LIZAKDS, AND SNAKES. 019 



adopted in the following synopsis of genera those wliicli have been 

 proposed by my i)redecessors for the various degrees of develoi)ment of 

 the limbs and toes. 



SYNOPSIS OF THE GENERA. 



I. Nostril pierced in the nasal, or Ixtween nasal and supraunsal or postnasal or first 

 npper labial, not touching the rostral. 

 A. Palatine bones separated on the median line of the palate ; no supranasal shields. 



No azygous occii)ital shield E(iernia Gray. 



Au azygons occipital shield, in contact with the interparietal ; tail prehensile. 



Corucia Gray. 

 AA. Palatine bones in contact on the median line of the palate. 

 1. Tympanum, if distinct, more or less deeply sunk. 



a. Pterygoid bones separated on the median line of the palate, the palatal 



notch extending anteriorly to au imaginary line connecting the 

 center of the eyes. 

 a. No supranasals. 

 Lateral teeth with obtuse or spheroidal crowns; au azygous occipital in 

 contact with the interparietal; subdigital lamella; divided. 



Trachysaurus Gray. 

 Lateral teeth with obtuse or si)heroidal crowns; subdigital lamellte 



undivided TiUqua Gray. 



An enormous crushing tooth on each side of each jaw. 



Hnnisplurriodon Peters. 

 /3. Supranasals present. 



Lateral teeth with compressed denticulated crowns; a series of suborbital 



shields Macroscinciis Bocage. 



Lateral teeth conical; two frontoparietals Mabmja Fitzinger. 



Lateral teeth conical ; one frontoparietal Monophi/aspia Cope. 



b. Pterygoids in contact (at least quite anteriorly) mesially, the palatal notch 



not extending anteriorly to l)etween the center of the eyes. 

 * Eyelids movable; digits with nonretractile claws. 

 t Supranasal plates present (tympanum not concealed). 

 t Lower eyelid with a transparent disc. 

 vA Frontoparietal single. 



Digits, 5-5 Emoa Gray. 



Digi ts, 5-4 Haf/ria Gray. 



Digits, 4-4 '. CMamela Gray. 



^^ Two frontoparietals. 



Digits, 5-5 Eiopa Gray. 



Digits, 2-3 Eitmecia Bocage. 



tt Lower eyelid scaly. 



^ Frontoparietal single. 



Digits, 5-5 Monophorus Cope. 



vS\S Two frontoparietals. 



l^igits, 5-5 Lepidothyris Cope. 



tt Supranasal plates wanting. 



t Lower eyelid with a transparent disc. 

 II Tympanum not concealed. 

 i^S Frontoparietal plate single. 



Digits, 5-5 Mocoa Gray. 



Digits, 4-5 Jleteropua Dnm^ril and Bibron, 



Digits, 1-2 lira chi/ si opus Dumeril and Bibron. 



Digits, 1-1 Oitcopus Cope. 



Digits, 0-2 OJlochinis Cope. 



Digits, 0-1 Soridia Gray. 



