Vol. III. May and June, 1902. Xos. i and 2. 



BIOLOGICAL BULLETIN. 



MATURATION OF THE EGGS OF DIEMYCTILUS 



TOROSUS. 



DR. HECTOR LEBRUN, BRUSSELS, BELGIUM. 



During my stay in California, where the Belgian government 

 sent me to verify the results of Dr. Eisen's investigations on the 

 testicles of the Batracoceps, and to study the eggs of these and 

 other Batrachians, the occasion also offered itself to study the 

 maturation process in Diemyctilus torosits. 



I knew, by the work of Professor Ritter, of the University of 

 California, that the copulation of this species takes place during 

 the months of March and April, and therefore immediately de- 

 voted my investigations to this subject. My material came 

 from Tocoloma, Marin County, California, where Professor Van 

 der Naillen called my attention to a large quantity of speci- 

 mens. In my previous publications, I have shown it to be ab- 

 solutely necessary to have the largest possible number of speci- 

 mens on hand to have good material in the different stages of the 

 maturation of the eggs, because these phenomena last only a 

 few days, and during this period, it is necessary to kill a large 

 quantity of females. All of these conditions are perfectly realized 

 in Tocoloma. 



By the kindness of the San Francisco Microscopical Society, 

 which generously opened to me its rooms and instruments, I be- 

 gan to study the material collected, and demonstrated my prepa- 

 rations at a meeting of the Society on the I 5th of May. 



As the present note is preliminary and a summary of the re- 

 searches made in California, my investigations will be continued 

 in Europe and published in the review (La Cellule). 



