RECORDS 85 



Another important piece of work taken up by Mr. Ritchey 

 was the appHcation of a color screen to celestial photography, 

 thereby adapting a visual telescope to photographic work. 

 Such a screen was used with the great forty -inch refractor of the 

 Yerkes Observator}', and photographs were exhibited showing 

 the excellence of ]\Ir. Ritchey' s work with this giant object 

 glass. S. A. Mitchell, 



Secretary 



SECTION OF BIOLOGY. 



December 8, 1902. 



The Section met at 8:15 P. M., Professor F. E. Lloyd pre- 

 siding. 



The minutes of the last meeting were read and approved. 



The Secretar}^ presented a letter from the Recording Secre- 

 tary-, regarding the estabhshment by the Scientific Alliance of 

 the Herrman Research Fund, stating also the method of pre- 

 senting and forwarding applications for grants. 



The following program was then offered : 



Edmund B. Wilson, Ox the Relation Between Localiza- 

 tion AND Cleavage as Elucidated by Experiments Upon 

 Merogenv. 



A. W. Grabau, The Phvi.ogenv of the Fusid.e. 



Summary of- Papers. 



Professor Wilson presented the results of his experiments 

 upon the eggs of Ccrebratiilus, which dealt with the problem of 

 germinal localization. It was found that isolated blastomeres 

 of the two-cell stage developed by partial cleavage, but that 

 dwarf larva of a normal structure were finally produced. The 

 upper part of a blastula, however, produced a larva which 

 lacked a perfect archenteron ; and a ventral portion of a blas- 

 tula became a pilidium which was devoid of an apical organ. 

 The development of egg-fragments obtained prior to the initial 

 cleavage, furnished particularly illuminating results. An egg- 

 fragment obtained before maturation, and fertilized later devel- 



