Here is one of them. This is not a new book (released in 1992), but it is worthy, as you say, it is hard to get a good book of comparative animal physiology. You will get a lot of information that you hardly found anywhere else, also the figures are pretty good (almost 1000 pages). Search for it in your bookstore nearby.
Comparative Animal Physiology
by Philip C. Withers Senior Lecturer in Department of Zoology, The University of Western Australia
Saunders College Publishing/Harcourt Brace Jovanovich College Publishers,
ISBN 0-03-012847-1 (International Edition)
Library of Congress Catalog Card Number: 91-050762
2345 032 987654321