DIA, The American Naturalist. [July, 
In Western Europe three species are recorded from the Miocene, 
and two from later beds. Of the former, B. affinis Owen is 
similar in size and character to the right whale, B. mysticetus, 
and B. primigenia Van Ben. to the shorter headed type repre- 
sented by the 2. cisarctica of the middle Atlantic (Plate XXIII.). 
The 2. dalenopsis Van B. is not over twenty feet in length. 
In the Plistocene beds of Sweden a true Balzna of the B. cisa- 
retica type has been discovered, and has been named 2. sveden- 
borgiana. It is thus evident that many species of whalebone 
b 
FIG. 8.—Cetotherium cephalus eye two-fifths natural size; individual represented 
in Fig. 7. Original; from Miocene of Maryland. 
whales have become extinct, some of them in comparatively 
modern times. Such is the Cetotherium robustum Lilljeborg, 
which is known from a few fragments, not fully fossilized, from 
an island in the Baltic, and from Cornwall, England. 
List OF THE Extinct CETACEA OF NORTH AMERICA. 
BASEERBBSAUNIDEL. -o 5.2.05 3 
Basılosaurus cetoides Owen. Ala., Miss. 
Doryodon serratus Gibbes. Ala., Fla. 
