AND AVES OF NOKTII AMERICA. 



PR0TE1 DA. 



Caudal vertebree and frontal bones distinct. Inferior pelvic elements not confluent. 

 (). o. maxillaria, prefrontalia and nasalia wanting; palatina and pterygoidea present. 

 Ethmoid* a vertical plate on each side the cerebral lobes. 

 Mandible toothed, teeth pleurodont. Ceratohyals, first pair connate. 

 No "postorbital and supertempora] bones." 



U ROD EL A. 



Usual cranial bones present, but pterygoids reduced or wanting. 



No "postorbital or supertempora] bones." 



Caudal vertebrae and frontal bones distinct. 



Ethmoid, a vertical plate on each side. 



Mandible dentigerous; teeth pleurodont. 



Inferior pelvic elements horizontal, in contact; no osseous pubis; ilium suspended to a 



sacral rib. 

 (Mostly no quadratojugal.) 



GYMN0PH1 DI A. 



Usual cranial bones present and distinct, including frontals and pterygoids. 



Caudal vertebra 1 distinct. 



No "postorbital or superteniporal bones. "f 



Ethmoid annulus surrounding cerebral lobes. 



Mandible; dentigerous; teeth anchylosed by their bases.J 



(A quadratojugal.) 



* Erroneously oalled orbitosphenoids by me. Journal Acad. 1866, (on Anura.) 



f When the temporal fossa is overarched, it is by expansion of the maxillary and quadratojugal. (Stannius says, 

 "Squama temporalis.") 



:|: The teeth of Csecilia are oompressed with a trenchant posterior edge, which is crenate after the manner of 

 Megalosaurus, Carcharias, etc. Thus to the numerous genera of Saurians and Selachians possessing this character, 

 must be added a Batrachian. 



AMEBI. rniLOSO. soc. — vol. xiv. 2 



