184 PROFESSOR STRUTHERS. 



groove of the internal series of foramina crosses the top of the 

 bone to join the fissure at its posterior end. Thereafter the 

 upper border of the bone is to the inner side of the fissure. The 

 'mental foramen is incomplete above, and in Megaptera also 

 in front, but is well defined on its floor at about 2 inches from the 

 symphysis. It is larger in Megaptera (height If inch) than in 

 B. musculus (height \\ to 1^ inch). In Megaptera it occupies 

 ]nore than the upper third of the symphysis, in B. musculus 

 scarcely more than the upper fourth. 



26. Relation of the Mandible to other Parts of the 

 Skull. — When the condyle is placed in contact with the middle 

 of the glenoid cavity, the tip of the coronoid process of the man- 

 dible is, in Megaptera, about 15 inches in front of the anterior 

 border of the temporal passage, and about 2 inches in front of 

 the ant-orbital process of the maxillary. Even with the man- 

 dible placed thus far back, the coronoid process would quite 

 clear the orbit and ant-orbital process of the maxillary in the 

 closing of the mouth. 



[In B. muscuhis, when the condyle is similarly placed in contact 

 with the glenoid cavity, the coronoid process stands below the orbit, 

 behind the middle of it, and could not but strike the malar bone in 

 the closing of the mouth. In order to enable the coronoid process to 

 clear the ant-orbital prominence, the condyle would have to be 

 advanced from the glenoid cavity for about 15 inches. In the 64- 

 feet-long B. musculus I found adhering to the condjde a temporo- 

 mandibular cushion, 30 inches in length, 24 in breadth, 15 to 18 in 

 height (this Journal, vol. vi., 1871, p. 123). How much of this lay 

 between the glenoid cavity and the condyle I Avas unable to note, the 

 mandible having been already detached.] 



As the position of the mandible with the condyle in contact 



with the middle of the glenoid cavity would give a projection at 



the symphysis of only 2| inches beyond the beak (and would in 



B. musculus place it 2 inches short of the beak), it is evident 



that there is naturally a considerable interval between the 



glenoid cavity and the condyle. If the temporal muscle goes 



to the coronoid process in Megaptera it will, after turning round 



the anterior boundary of the temporal passage, have a long way 



to travel, and that by passing close below the soft parts of the 



orbit. Dissection of the muscles and other soft parts here is 



necessary to the interpretation of the bone at and near the 



coronoid process. 



