WHALEBONE WHALES—MACKINTOSH 259 
formation on breeding and growth is required, and the indications of 
age from the baleen plates require further attention. The present 
article is not concerned with anatomy and physiology, but a factory 
ship would offer scope for further progress in these fields. The breed- 
ing cycle of humpbacks could be studied to much advantage if a suffi- 
cient number of this species could be examined in winter at a tropical 
land station. 
Whale marking also needs to be continued. It provides data on 
distribution and migrations, on growth and age, ‘and on the propor- 
tions in which different species are removed from the stock by hunt- 
ing. Marking should if possible be extended to regions other than the 
Antarctic, such as the warmer southern latitudes in winter, if sufficient 
numbers of whales can be located. The statistics of catches also will 
continue to provide material which is instructive in itself and valu- 
able for correlation with other data. New technical devices will no 
doubt provide new methods of research. “Asdic” should be helpful 
in studying the habits of whales especially in regard to their under- 
water movements, and radar might be of much value in counting the 
number of whales in a measurable area. There are clearly great 
possibilities in the use of aircraft. The vast extent and severe 
weather conditions of the principal resorts of whalebone whales would 
involve difficulties, but aerial observations over sample areas in com- 
parable conditions might go far to assist in the much needed census 
of the populations. Aerial photographs also can be very informative. 
VII. SUMMARY 
(1) The whaling industry has provided both the facilities and the 
stimulus for modern research on the general biology of whales. The 
principal methods of investigation are (a) anatomical examination, 
(b) observations at sea, (c) the marking of whales, (d) analysis of 
the statistics of the whaling industry. (2) The whalebone whales are 
migratory animals, inhabiting high latitudes in summer where food , 
is plentiful, and moving into warmer waters in winter where there is 
little or no food, but where breeding takes place. The Greenland right 
whale does not move far from the Arctic regions and is not found 
in the Southern Hemisphere. The black right whales of the north 
and south do not migrate far and are separated by a wide tropical 
belt. The humpback migrates from the polar ice to the Equator, and 
frequents tropical coastal waters in the winter months. In the South- 
ern Hemisphere it is segregated into several communities which have 
separate migration routes, and between which there can be little inter- 
change. Blue and fin whales undertake less regular and extensive 
migrations. They are not segregated like the humpbacks, but show 
a slight tendency to concentrate in the same regions. Gray whales 
