338 



THE ANATOMY OF VEETEBRATED ANIMALS. 



with the bodies of the vertebrae only by ligament. The chief 

 connection of all the ribs, therefore, and the only connection 

 of most of them, is with the transverse processes of the verte- 

 br£e. The short and broad sternum unites only with the iirst 

 rib, and the union is direct, so that there are no sternoiujstal 

 libs. 



Fig. 105. — "Ear-booes" of the adult Balama Avstraivt. — Seen from within In the npi:ei 

 figure; fi-om without in the lowor. Ev-., Eustachian canal; Au.^ oxtemal auditory 

 meatus ; Sty.-, ossified root of the styloid process. 



The skull (Fig. 104) is exceedingly large in proportion to 

 the body, and nearly symmetrical. The nasal bones, JVu., 

 though short, are longer, and more like those of ordinary 

 mammals, than is the case in other Cetacea. The maxilla, 

 Mic., extends outward in front of the great supraorbital process 

 of the frontal, ^., but it does not cover the frontal bone. 

 There is a distinct lachrymal. Each ramus of the mandible, 

 Mil., is convex outward and concave inward ; and the space 

 between the rami of the mandible is very much greater than 

 the width of the maxillo-premaxillary part of the skull, which 

 tapers to its anterior end, and is more or less convex upward 



