SCHULTE, SEI WHALE. 407 



border is attached the ventral border of the parietal plate in the region from which springs the 

 orbito-parietal commissure. The rostral extremity of this border is in relation to the tip of the 

 external pterygoid to which it is firmly united by fibrous tissue. The caudo-ventral border 

 forms a free edge overhanging the proximal portion of the shaft of Meckel's cartilage and the 

 ossicles of the middle ear. At its caudal extremity it meets at an obtuse angle the crista paro- 

 tica. The rostro-ventral border is also free, and is in contact by one extremity with the pre- 

 facial commissure, by the other with the shaft of Meckel's cartilage. 



The tegmen tympani is related by its ectal surface to the squamosal by its ental surface 

 to the cavum tympani and the otic capsule, filling in like a wedge the space between the two. 



