SKELETON OF THE CROCODILE. THE SKULL. 255 



ascending process with the descending process of the pre- 

 f rental. 



The pterygoids (tigs. 43, A, 4, and 45, 11) are a pair of 

 large bones, each consisting of a median more or less vertical 

 part, which becomes ankylosed to its fellow in the middle 

 line early in life, and of a wide horizontal part which meets 

 the transpalatine. They completely surround the posterior 

 nares (fig. 43, A, 5) and their median portions form the whole 

 boundary of the posterior part of the narial passage, and assist 

 the palatines and vomers in bounding the middle part. 'The 

 horizontal parts form the posterior part of the secondary palate, 

 while the dorsal surface of each looks into the pterygoid fossa, 

 a large cavity lying below the quadrate and quadratojugal at 

 the side of the skull. The lateral margin adjoining the trans- 

 palatine is in the fresh skull terminated by a plate of cartilage 

 against which the mandible plays. Dorsally the pterygoid 

 articulates with the basisphenoid, quadrate, and alisphenoid. 



The transpalatines (fig. 44, 11) connect the pterygoids with 

 the jugals and maxillae, articulating with each of the three 

 bones by a long pointed process. The jugal process meets also 

 a down-growth from the postfrontal. 



The jugals or molars (fig. 44, 5) are long somewhat flat- 

 tened bones which are united to the lachrymals and maxillae 

 in front, while passing backwards each is united behind to the 

 quadratojugal (fig. 44, 12), the two forming the infratemporal 

 arcade which constitutes the external boundary of the orbit 

 and lateral temporal fossa. The jugal is united below to the 

 transpalatine, and the two bones together form an outgrowth, 

 which meeting that from the postfrontal forms the postorbital 

 bar, and separates the orbit from the lateral temporal fossa. 

 The quadratojugals are small bones and are united behind 

 with the quadrates. 



The quadrate (figs. 43, A, 13 and 44, 8) of each side is 

 a large somewhat flattened bone firmly fixed in among the 

 other bones of the skull. It is terminated posteriorly by an 



