Ill 



SKULL 



41 



bones (EX.OC) which bound the sides of the foramen 

 magnum, nearly uniting above and below it, and extending 

 over a considerable portion of the posterior surface of the 

 auditory capsule. These bones are the exoccipitals. In 



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front of each exoccipital is another irregular bone (PR.OT) 

 forming the front part of the auditory capsule, and called 

 the pro-otic. Each pro-otic is separated from the corre- 

 sponding exoccipital, in young frogs, by a band of cartilage, 

 but in old specimens the two bones are more or less 

 completely united. 



