** ■ 



** New Theories: 

 A — Body-weight: Egg-weight Index. 

 B — Temperature and Ascent Theory. 



* Bird temperature. 

 Rapidity of metabolism or "swiftness of life." 



* Temperatures, incubation lengths, and taxo- 

 nomic position. 



**** Collateral evidence. 



6 — Present data and this new theory. 



7 — Usefulness of new theory. 



8 — Does correlation of temperature and incubation length 

 benefit species? 



9 — Data need for further study of this problem. 



10 — Conclusions — 

 A — Minor. 

 B — Major. 



11 — List of incubation periods. 



12 — Bibliography. 



