— ni 



Sketch of the head, showing the position of the 

 lower jaw relative to the skull- 



doubts were raised on different sides as to the correctness of the position in 

 which the mandibles had been fixed relative to the rest of the skull. 



It may be mentioned sub limine that there was no literature dealing 

 with this matter available to me. In the second place the various illustrations 

 of finner-skeletons of divers musea show too little agreement to enable the 

 question to be solved by means of them. Let it be borne in mind that since 

 nearly all mammalia chew their food, the mandibles of those animals must 

 have a fixed fulcrum which is found in the articular condylus of the lower jaw 

 fitting into an articular cavity at the base of the squamose portion of the 

 temporal bone. Seeing that mastication is out of the question in the case of 

 Balaenoptera the necessity for this articulation does not exist here. 



Again, it must be clearly understood that just in the case of these 

 furrowed whales to a greater extent than with the smooth, furrowless repre- 

 sentatives of the group, the mandibular- and throat part of the body is 

 extraordinarily developed, while the throat pleatings make it possible to in- 

 crease the capacity of the lower jaw even considerably more. In connection 



