ANATOMY OF THE HEAD OF THE GREEN TURTLE. 389 



condylar rami [18] hide that of the basioccipital [19] dorsally 

 except within the foramen, and stand out beyond it later- 

 ally. Between the three facets is a deep fossa, which for 

 the most part is filled by the articular cartilage, hut into 

 the upper part of which the ligamentum opieis dentin is 

 inserted. 



The paroccipital fossa (fossa p-iroccipitalis) [61] is a 

 concave area on either side of the condyle upon the 

 posterior surfaces of exoccipital and basioccipital bones, at 

 the junction of paroccipital and condylar rami. The fossa 

 is the site of insertion of one of the cephalo-cervical 

 muscles. Above the paroccipital fossa are the external 

 apertures of the hypoglossal canals [53] upon the body of 

 the exoccipital bone. 



The paroccipital process (processus puroccipittdis) [12] 

 is a prominent outstanding conical tubercle lateral to the 

 paroccipital fossa. Three bones enter into its formation, 

 medially are the paroccipital rami of exoccipital and basi- 

 occipital, laterally the process is completed by the par- 

 occipital lamina of the pterygoid. This process is very 

 constantly present in reptilian skulls reaching its minimum 

 of development in some Crocodilia. The basioccipital bone 

 is the most constant component, the exoccipital next in 

 constancy, the pterygoid least constant. I believe that 

 its position and constitution are sufficient justification for 

 the name here applied to it. 



The external aperture of the carotid canal (eanulis cor- 

 oticus) [13] is on the posterior extremity of the pterygoid 

 immediately to the outside of the paroccipital process. 



Immediately above the paroccipital process is the 

 posterior aperture of the spacious acustico-jugular cavity 

 [65]. 



The parotic process (processus parotic us) forms the roof 

 of this cavity. The prootic bone is incorporated in the 



