Cranial Characters of Iguanoid Lizards. 413 



2. ConoJopkus, Fitz.* — All the teeth trilobate. Prte- 

 maxillary not extending as far as the posterior border of the 

 nasal fossae ; the length of the latter nearly equals their 

 distance from the orbits. Pr^efrontal not entering the nasal 

 fossa. Postfronto-squamosal arch longer than the orbit; 

 postfrontal longer than deep. Transpalatine in contact with 

 palatine. Basisphenoid short and much constricted behind 

 the basipterygoid processes, as in the preceding. 



3. Brachylophus ^ Wngl. — All the teeth tricuspid. Prce- 

 maxillary not extending as far as the posterior border of the 

 nasal fossae ; the length of the latter equals their distance 

 from the orbit. Prefrontal not entering the nasal fossa. 

 Postfronto-squamosal arch short, not longer than the orbit ; 

 postfrontal as long as deep. Transpalatine not in contact 

 with palatine. Basisj)henoid as in Gyclura^ rather elongate 

 and much constricted behind the basipterygoid processes. 



4. Iguana^ Laur. — Lateral teeth with numerous denticles. 

 Prajmaxillary not extending as far as the posterior border of 

 the nasal fossaj ; the length of the latter nearly equals their 

 distance from the orbits. Prefrontal not entering the nasal 

 fossa. Postfronto-squamosal arch slender, short, not longer 

 than the orbit ; postfrontal as long as deep. Transpalatine 

 in contact with palatine. Basisphenoid short and but slightly 

 constricted behind the basipterygoid processes. 



5. Metopoceros^ Wagl. — Lateral teeth with four to seven 

 cusps. Premaxillary not extending as far as the posterior 

 border of the nasal fosse ; the length of the latter much 

 greater than their distance from the orbits. Prefrontal entering: 

 the nasal fossa. Postfronto-squamosal arch wide, a little 

 longer than the orbit ; postfrontal longer than deep. Trans- 

 palatine not in contact with palatine. Basisphenoid inter- 

 mediate between Iguana and Cyclura. 



6. Cyclura, Harl. — Lateral teeth with three to six cusps. 

 Premaxillary extending as far as the posterior border of the 

 nasal fosse ; the length of the latter not more than their 

 distance from the oibits. Prefrontal not entering the nasal 

 fossa. Postfronto-squamosal arch long and wide, intermediate 

 between Metopoceros and Ctenosaura ; postfrontal longer than 

 deep. Transpalatine not in contact with palatine. Basi- 



* The cranial characters are talfen from the figure given by Stein- 

 dachner, Festschr. zool.-bot. Ges. Wien, 187<j, pi. v. 



