Vol. l\ . April, 1903. Xo. 5 



BIOLOGICAL BULLETIN. 



NOTES ON MEROGONY AND REGENERATION IN 



RENILLA. 



EDMUND B. WILSON. 



H. B. Torrey ' has published a brief note on regeneration in 

 Rcidlla in which he shows that the young colonies possess a 

 high regenerative capacity and records some valuable prelimi- 

 nary observations, but owing to the difficulty of procuring suffi- 

 cient material he was unable to carry these observations far 

 enough to reach a decisive result on some of the important ques- 

 tions concerned. During the summer of 1902, after repeated 

 failures in preceding years, I was fortunate enough to secure at 

 Beaufort, N. C., 2 four lots of fertilized eggs from which hun- 

 dreds of young colonies were reared (they were kept alive three 

 weeks but produced only the two primary buds) and also a con- 

 siderable number of older but still young colonies, obtained from 

 the sand. I was thus able considerably to extend Torrey' s ex- 

 periments and also to make observations on the development of 

 egg-fragments that yielded some suggestive results. 



(rt) THE DEVELOPMENT OF EGG FRAGMENTS. 

 All efforts failed to fertilize the eggs artificially, so that only 

 fertilized eggs were available for experiment, but these can 

 easily be cut individually with the scalpel into two or more 

 pieces. As I showed in my paper of 1882 3 the cleavage-nucleus 

 divides several times (from three to five) before cleavage of the 

 cytoplasm occurs, the egg usually segmenting, from two to three 

 hours after it is laid, 4 at once into eight or sixteen blastomeres 



1 " Some Facts Concerning Regeneration and Regulation in Renilla" BlOL. 

 lli'i.!,., Vol. II., p. 6, 1901. 



2 1 am indebted to the Hon. G. M. Bowers, U. S. Commissioner of Fisheries, foi 

 the privilege of occupying a table at the Beaufort laboratory, and to Dr. Caswell 

 Grave, director of the laboratory, for his kind cooperation. 



3 "The Development of Renilla" Phil. Trans., Vol. III., p. 24. 



4 As I found twenty years ago the eggs are always laid between 5 : 3 an d 6 A. M. 



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