ia ad Recent Literature. 489 
how fara given species has journeyed away from its proto-avian stem, 
since it seems probable that the farther a bird is from its primitive an- 
cestry, provided it does not later degenerate, the higher will be its tempera- 
ture. I doubt very much that the present mainstays of taxonomy can 
alone measure this space between pro-bird and super-bird. I believe that 
future students of avian taxonomy will have to give more consideration, 
not only to embryology, but also to bird physiology, in order to correctly 
locate and plot the mileposts in a bird’s journey.” 
In considering his data Dr. Bergtold calls attention to the real and 
apparent time of incubation, the latter being the actual time plus that due 
to errors of observation or to the fact that in some species early laid eggs 
are incubated to some extent during the laying of the subsequent ones — 
facts that should be considered in making use of published data. The 
lamentable scarcity of information on the weights and temperatures of 
birds is emphasized as well as the numerous opportunities for experimental 
investigation which the problems here discussed offer. 
Dr. Bergtold’s book is a valuable contribution to a neglected line of 
research and can be read with profit by all ornithologists. That it does 
not represent the last word on the subject the author is the first to admit 
but it is so suggestive throughout that it cannot help but attract others to 
this interesting field, and we trust that ere long the accurate detailed data 
necessary for the final consideration may be forthcoming. And in this 
work our Australian friends can give valuable assistance by supplying the 
data on the temperature of the Megapodes which Dr. Bergtold has been 
unable to obtain. 
Pending the accumulation of further data we may accept his conclusions 
as the most plausible solution of the problem yet presented, and even if, 
as the author suggests, they be not entirely original they are certainly more 
concisely and convincingly set forth than has been done by anyone else. 
We regret that the book shows numerous evidences of hasty proof- 
reading resulting in some misleading errors, as ‘“‘egg-white”’ for egg-weight, 
on page 44. We also notice on page 16 a reference to the relationship of 
“the finches of Australia....to their cousins of the North” but the so 
called ‘finches’ of Australia are really Weavers and belong to a different 
family.— W. S. 
Howell on the Birds of the California Coast Islands.1\— This ad- 
mirable paper forms No. 12 of the ‘Pacific Coast Avifauna’ published by the 
Cooper Ornithological Club and maintains the same excellence in style and 
typography presented by recent numbers of the same series. Mr. Howell 
having formed a personal acquaintance with the birds of some of the islands, 
was impressed with the need of a comprehensive treatise on the avifauna 
1 Birds of the Islands off the Coast of Southern California. By Alfred Brazier Howell. 
Pacific Coast Avifauna No. 12. Cooper Ornithological Club. June 30,1917. pp. 1-127. 
Price $1.50. 
