THE FITNESS OF RIGHT WHALES 75 



interesting variability not uncommon in dwind- 

 ling structures, and their long lingering may be 

 partly due to the fact that they afford insertion 

 to certain small muscles. In some unborn whales 

 there are two small button-like projections 

 external hind-limbs literally at a vanishing-point. 

 Absolutely vestigial are the Right Whale's teeth, 

 which never cut the gum and are absorbed before 

 birth. Yet there is a first set and a second set as 

 in ourselves. 



There is much that is interesting in the sense- 

 organs. The eye is without the usual eye-cleaning 

 third lid, its absence being compensated for by 

 the continual washing; its practical absence in 

 our own case is compensated for by the frequent 

 movements of the upper eyelid. The smelling 

 membrane is degenerate, and there are other 

 olfactory deficiencies, intelligible enough in animals 

 of terrestrial origin which have come to be habitually 

 submerged. The outer ear passage is open to the 

 water, and the drum is so fixed that it cannot 

 vibrate; it is probable that the chief use of the 

 whale's ear is in equilibration, and in making the 

 animal aware of changes in the pressure of the water 

 as it dives or rises. If sounds pass to the ear- 

 ossicles and the inner ear, it must be through the 

 bones of the skull. 



The Black Right Whale is not gregarious, but a 

 pair may keep company for long, and they may be 

 followed for over a year by their calf. The ordinary 

 rate of swimming is leisurely, about four miles an 



