594 M. L. DOLLO. 



Pstfr Sq 



J Qj Q 



Sauropsida, 



My reasons are as follows : 



1st. The ancient Reptiles (Ichthyosauria, Plesiosauria, Dino- 

 sauria, &c.) possessed an ossified quadrato jugal 



2nd Amongst the existing Sauropsida, Birds, Crocodiles, 

 and Chelonians, as well as Hatteria, possess one still. 



3rd. This latter animal represents amongst the Lacertilia a 

 primitive type, as it is closely allied to the Triassic Rhyncho- 

 saurus. 



4th. The quadrato-jugal exists still in a ligamentous con- 

 dition in the Ophidia and Lacertilia, and this is certainly an 

 indication of rudimentation since in all the Chalcideee and ophi- 

 diiform Scincoidea the squamoso-postfrontal arch likewise 

 becomes ligamentous 



Let us now consider by what peculiarities in its connections 

 the quadrate of Sauropsida is distinguished, and then examine 

 whether these peculiarities are also to be found in M. Albrecht's 

 quadrate. 



The quadrate of Sauropsida may be in relation — 



1st. At its proximal extremity with the squamosal, the pa- 

 rietal, and the parotic process (Iguana). 



2nd. At its proximal extremity again with the malleus 

 (Uromastix). 



3rd. At its distal extremity with the mandible and the 

 pterygoids (Iguana). 



4th. At its distal extremity again with the quadrato-jugal 

 (Crocodile). 



5th. Occasionally with the postfrontal (Rhynchosuchus). 



6th. Lastly, with the tympanic membrane, which is inserted 

 into it in a posteriorly placed concavity, which might be termed 

 the tympanic concavity (Iguana). 



