413 
Cranial Characters of Iguanoid Lizards. 
2. Conolophus , Fitz.* — All the teeth trilobate. Pre- 
maxillary not extending as far as the posterior border of the 
nasal fosse ; the length of the latter nearly equals their 
distance from the orbits. Prefrontal 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. Brachglophus y Wagl. — All the teeth tricuspid. Pre- 
maxillary not extending as far as the posterior border of the 
nasal fosse ; 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. Basisphenoid as in Cyclura, rather elongate 
and much constricted behind the basipterygoid processes. 
4. Iguana , Laur. — Lateral teeth with numerous denticles. 
Premaxillary not extending as far as the posterior border of 
the nasal fosse ; 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 orbits. Prefrontal not entering the nasal 
fossa. Postfronto-squamosal arch long and wide, intermediate 
between Metopoceros and Gtenosaura ; postfrontal longer than 
deep. Transpalatine not in contact with palatine. Basi- 
* The cranial characters are taken from the figure given by Stein- 
dachner, Festschr. zool.-bot. Ges. Wien, 1876, pi. v. 
