DEVELOPMENT OF THE SKULL OF EMYS ^ 757 



12. The nervus glossopharyngeus passes through the cavity 

 of the otic capsule in the sulcus glossopharyngeus which is situ- 

 ated on the posterior wall of the cavum cochleae immediately 

 ventral to the cavum ampullare posterius. The nerve perforates 

 the median capsular wall by means of the foramen glossopharyn- 

 gei internum and the outer wall by the foramen glossopharyngei 

 externum. 



13. The cavum cochleae is developed in a posterior direction 

 so that the nervus glossopharyngeus passes through it. 



14. The cavity of the otic capsule is not divided by a septum 

 intervestibulare as in Lacerta. 



15. The median capsular wall is perforated anterior to the 

 foramen glossopharyngei internum by the foramina acustica 

 anterius and posterius and endolymphaticum; besides these are 

 one or two smaller foramina one of which is for a blood vessel. 



16. The foramen facialis lies anterior to the otic capsule and 

 opens laterally into a depression, the fovea geniculi. 



17. The foramen abducentis passes horizontally forward through 

 the base of the pila prootica. 



18. The fenestra prootica is large and unclosed dorsally because 

 of the absence of a taenia marginalis to unite the distal end of the 

 pila prootica and the otic capsule. 



19. The fenestra hypophyseos is large and accommodates, 

 besides the hypophysis cerebri, the arteriae carotides internae as 

 they pass into the cavity of the cranium. 



20. The fenestra metoptica, for the accommodation of the 

 nervi oculomotorius and trochlearis, is in the form of a narrow 

 slit and, like the fenestra prootica, is unclosed dorsally. 



21. The planum basale projects laterally in the region of the 

 crista sellaris beyond the attachment of the otic capsule to form 

 the crista basipterygoidea which is apparently homologous with 

 the processus basipterygoideus and with which articulates a 

 rudimentary imperfectly chondrified cartilago articularis. The 

 ramus palatinus nervi facialis passes ventrally from the ganglion 

 geniculi a short distance behind the cartilago articularis and then 

 extends anteriorly on the median side of the cartilago articularis 

 in the sulcus cavernosus. 



JOURNAL OF MORPHOLOGY, VOL. 23, NO. 4 



