28o REPORTS ON INVESTIGATIONS AND PROJECTS. 



Tufts College, Massachusetts (see Year Book, 1911, p. 241) ; to Dr. Daven- 

 port Hooker, of Yale University, New Haven, Connecticut, from April 4 to 

 May 21, 1912, and Dr. David H. Tennent, of Bryn Mawr College, from 

 May 13 to June 20, 1912. 



Dr. Hooker continued his experimental researches on the growth of iso- 

 lated tissues, and histological elements in the serum of Selachian embryos ; 

 and Dr. Tennent studied the hybridization in the eggs of echinoderms. 



Riddle, Oscar, University of Chicago, Chicago, Illinois. Grant No. 799, 

 allotted February 15, 1912. Preparation for publication of the manu- 

 scripts of the late Dr. C. O. Whitman, provision for care and mainte- 

 nance of the Whitman pigeon collection, and continuation of investiga- 

 tions necessary for completion of Dr. Whitman's manuscripts. $4,400 



The more important accomplishments of the present year are : 

 (i) The partial arrangement of the parts of the Whitman manuscripts 

 that bear on the "shifting of dominance." 



(2) Other work on these manuscripts, including the examination, typing, 

 and duplication of parts, and the assembling of most parts bearing on the 

 subject of "behavior." 



(3) Very extensive investigations on a comparison of the chemistry and 

 energy content of the male- and female-producing eggs of pigeons ; it is as 

 yet too early to state the results of these studies. 



(4) The discovery of evidence of the existence of two kinds of females — 

 one more masculine than the other — among the hybrids of Turtur orientalis 

 and T. alba. In other words, some evidence is found that sex is not a true 

 alternative character, but a graded character. 



(5) The continuation and extension of some of Professor Whitman's 

 studies on the method of inheritance in pigeons, and on the nature and mean- 

 ing of mutants. Of considerable interest here is the result that three of the 

 fourteen F^ offspring of an apparent "mutant," T. orientalis, mated with a 

 normal T. orientalis showed traces of the mutational character ; two hatched 

 still later showed this character almost complete ; these five were all hatched 

 late in season from birds overworked in reproduction — conditions similar to 

 those under which the original mutant was obtained. 



(6) Findings on the physiology of reproduction which show: (0) that 

 fertility of the bird's egg is affected by feeding of sodium benzoate only when 

 fertility is weak; (b) new evidence that a sudden change in the growth rate 

 of ova of the fowl occurs when the ova reach a diameter of 6 to 7 mm. ; (c) 

 that the chemical composition of the membrane (follicular) surrounding the 

 egg has a very high phosphatid content at the time when rapid growth begins ; 

 (d) the subgerminal cavity of the sauropsidan blastoderm and egg is due pri- 

 marily to imbibition of water from the albumen by the egg-yolk, and can 

 arise in unfertilized eggs independently of the development of an embryo. 



