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 
