` 
103 ^. Transactions.—Zoology. 
hemisphere; but it is evident, from an examination of the drawings 
representing the three views of a foetal Cachalot (Catodon), in the Museum of 
the Royal College of Surgeons, that the remarkable asymmetry exists already 
in that early state of existence. 
On the other hand, I may ask why should the Balenide have a 
symmetrical skull, breathing, as they. do, exactly in the same manner as the 
toothed whales?  Eschricht, who has described the important changes which 
the skulls of Ше Balenide undergo, has shown that they are in the fetal 
state quite symmetrical, although later on slight inequalities in the maxille 
are sometimes discernible. 
As far as I am aware no cognizable reason can be given to account for this 
asymmetry in the skull of the toothed whales, and we are, therefore, almost 
led to assume that some of their remote ancestors were deformed by some 
accident, and that thus this asymmetry of the skull was inherited by their 
progeny to a more or less extent; because it is difficult to believe that in the 
struggle for existence, in the adaptation to altered circumstances and a 
different mode of life, this strange asymmetry could be of any vital 
importance. 
The study of the ontogeny of this species, and of the phylogeny of the 
family to which it belongs, and of its extinct ancestors is, therefore, of the 
highest importance in considering the question of the origin of species, because 
every step in that direction is a clear gain to science. 
It may be possible that this point has already been treated at length by 
Some naturalists, but I am not aware that this is the case, and my wish to 
draw the attention of my brother naturalists in New Zealand and other 
countries—where an opportunity is offered by acquiring specimens of toothed 
whales in all stages of growth, to study this striking fact in osteology—has 
been my only motive for alluding here more fully to it than I should otherwise 
have done. 
