346 TOOTH GERMS IN WHALEBONE WHALES CHAP. 
driven upwards by the forcible expulsion of air from the lungs. 
But for the most part the water which is spouted is simply 
condensed breath. 
Like some, but not all, other aquatic Mammalia the Whales 
have apparently no external ear. Indeed the opening of the ear 
is excessively small. In a huge Rorqual it will “admit a quill”; 
and although “a quill” is rather vague, we may fairly allow any 
sized quill without proving that the orifice of the auditory 
passage is anything but exceedingly minute. As a proof, added 
to so many, that the Whales are the progeny of terrestrial creatures, 
we have the occasional traces of external ears.’ 
Fic. 182.—Left lower jaw of foetus of Lalaenoptera rostrata. Inner aspect, 
natural size, showing teeth. (After Julin.) 
Whalebone Whales never possess permanent teeth as well as 
the baleen; but in the foetus are more than traces of true teeth, 
which, however, never arrive at maturity. The whalebone itself is 
described later (p. 354). That the Whalebone Whales possess teeth 
while in the foetal condition was discovered so long ago as 1807. 
It has since been confirmed by many observers. Not only is there 
one set of teeth developed in the foetal Balaenoptera but two, 
of which one comes to a greater maturity; the other, in fact, 
remaining at a very early stage of development. The more 
complete dentition belongs to the milk series, as is the case with 
the Toothed Whales. A very interesting conclusion with regard 
to the derivation of the simple conical teeth of Whales seems to 
follow from the development of these structures in Lalaenoptera. 
There are in the young foetus fewer teeth than in the more 
advanced embryo. Now in the younger embryo some of the 
teeth are furnished with more than one cusp; they are bi- or 
even tri-conodont. As Sir R. Owen observed, the teeth—some of . 
1 These have been recorded by Professor Howes in the Porpoise. 
y 
