The internal modifications which the whales underwent as they assumed an aquatic existence are fully as remarkable as the external changes. In the section on osteology it has been explained how, in living cetaceans, the entire skeleton is loosely articulated so that great flexibility and freedom of movement is given to the body, how the neck is shortened and the vertebræ have become thin and closely packed together to support the large head, and how the breast bone is reduced and the ribs so loosely articulated to the vertebral column that the huge lungs have full power of expansion. All these are necessary modifications of the mammalian skeleton which have been caused by the change from a terrestrial to an aquatic existence. The lungs of the Cetacea are unlobulated and of extraordinary size; the diaphragm, the muscular partition which separates the thoracic from the abdominal cavity, is oblique, and the brain greatly convoluted and of a high type; the brain is especially notable for the loss of the olfactory, or smelling portions, which are of no use to an aquatic mammal. Thus it is apparent in a review of only the most obvious changes what a wonderful example of adaptation to environment is furnished by the Cetacea. INDEX _Aate_ (_Calanus finmarchius_), 126 _Acinomyx jubatus._ _See_ Cheetah Admiralty Island, Alaska, 4 Tyee Company erected station on, 185 Aikawa, 91, 130, 143, 152, 235, 263 _Airondo Maru_, 105, 130 _Akebono_, 105 Alaska, vii, 4, 5, 46, 59, 63, 64, 143, 148, 158, 175, 180, 230, 252 Alaska Whaling Company, 5 _Albatross, U. S. S._, 77, 78 Aleutian Islands, 5, 230 Allen, Doctor Glover M., 45 Allen, Doctor J. A., vii Amagansett, 253, 255 Ambergris, 225, 226, 227 America, Pacific Coast of, 185, 186 _American Museum Journal_, viii American Museum of Natural History, vii skeletons of all the large Japanese cetaceans in, viii trustees of, viii, 230, 235, 255, 266 American West Coast whaling industry, vii American whaling ships, 189 Americans, 23 Andersen, Captain Y. E., vii, 61, 92, 95, 100, 101, 102, 104, 105, 107, 108, 110, 111, 113, 114, 115, 117, 120, 121 Andrews, Yvette Borup, vii Antarctic circle, 304 Antarctic Ocean, 124, 184 Antwerp, 265 _Aosaki_ (red blubber whale), 214 Apple Island, 269 Arctic Ocean, 186, 249, 263 Arctic Region, 184 Argentina, 9, 304 Arytenoid cartilages, 43 Atlantic finwhalers, 176 Atlantic Ocean, 183, 184, 304 Australia, 6, 169, 248, 265 Baffin Bay, 296 _Balænopterinæ_, 183 Balcom, Captain, 24, 25, 30 Baleen, 37, 69 objects made of, 90, 158 value of, 247, 248, 253 Baleen whales, food of, 67 Banks Land, 249 Barclay Sound, 4, 22, 24 Barnacles, 65, 66, 211, 248 Barneson, Captain John, viii, 4 Barrel view from the crow’s nest, 26 Basques, 245 Bay City, Washington, 5 Bay of Biscay, 245, 296 Bay of Islands, 6 Beluga or white whale, 54