THE GENEALOGICAL HISTORY OF THE MARINE 
MAMMALS. 
By Prof. O. ABEL. 
The old Norwegian “ King’s Mirror” of the thirteenth century 
enumerates a series of whales of commercial importance, among which 
we can recognize with certainty no less than thirteen kinds. While 
it is true that in this work correct observations are mingled with 
erroneous traditions, it is, nevertheless, one of the most valuable 
natural history documents of the Middle Ages, unhampered by preju- 
dices and the burden of antiquated learning. 
How greatly has our knowledge of marine mammals increased 
since that time, and how much have our views regarding them 
changed! Knowledge in this field has increased extraordinarily, 
especially during the second half of the last century. Although we 
have brought it to so great perfection compared with the King’s 
Mirror, nevertheless, we still meet to-day with false ideas regarding 
marine mammals and their origin. Step by step we have brought 
ourselves to perceive that the ancestors of the whales, of the sea-cows, 
and of the seals are to be sought among land mammals, from which 
the different branches have been adapted independently for an aquatic 
life, and have developed separately. 
We have approached nearer the solution of the problem of the 
origin of marine mammals in different ways. The first was through 
the investigation of embryos, for the purpose of finding ancient 
characters inherited from ancestors. The second way was by seek- 
ing through comparison of the organs of adult animals to reach 
conclusions regarding their relationship and derivation. 
The direct evidence of the ancestors of living animals in the geo- 
logical strata will, however, always be of decisive significance. The 
discoveries made in this field in late years have been so unexpected 
that the time seems favorable for rendering the present state of our 
investigations accessible to a larger circle of readers. 
As a preliminary, we shall make a brief survey of living marine 
mammals, and afterwards consider their history more in detail. 
4'Translated, by permission, from ‘*‘ Meereskunde,” Berlin, Jahbrgang I, 1907, 
Heft 4. 
473 
