122 RECORDS 



5. Trifid nebula in Sagittarius ; exposure 3 hours. 



6. The Pleiades, showing nebulosity. 



7. Ring nebula in Lyra. 



8. Crab nebula in Taurus. 



9. Small nebula in Andromeda. 

 10. Spiral nebula M, 74, in Pisces. 

 II." " in Pegasus. 



12. " ** in Triangulum. 



13. ** ** in Ursa Major. 



14. Net-work nebula in Cygnus. 



15. M, 13, in Hercules — star cluster. 



Reference was made to Keeler's determination of the radial 

 velocities of nebulae and to the distances of these masses. 



After a brief discussion of the paper, the Section adjourned. 



F. L. Tufts, 



Seci'etary. 



SECTION OF BIOLOGY. 



April 8, 1901. 



Section met at 8:15 P. M., Mr. M. A. Bigelow presiding. 

 The minutes of the last meeting of Section were read and ap- 

 proved. 



The following program was then offered : 



E. B. Wilson, The History of the Centrosomes in Arti- 

 ficial Parthenogenesis, and its Relation to the Phenom- 

 ena OF Normal Fertilization. 



F. S. Lee, Some Observations on Rigor Mortis. 



Summary of Papers. 



In continuation of his communication given at the December 

 meeting. Professor E. B. Wilson presented the results of fur- 

 ther studies on the development of the unfertilized eggs of 

 Toxopneustes when treated by Loeb's magnesium chloride 

 method. The principal points considered were the origin and 

 history of the centrosomes and the general relation of the phe- 

 nomena to those occurring in normal fertilization. Evidence 



