Vol. XVII. October, 1909. No. j. 



BIOLOGICAL BULLETIN 



SOME EGG-LAYING HABITS OF AMPHITRITE 

 ORNATA VERRILL. 



JOHN W. SCOTT. 



Several years ago while engaged in working out the develop- 

 ment of the unfertilized eggs of Amphitritc I had occasion to col- 

 lect large numbers of these worms. Mead, who worked on the 

 cell-lineage of this annelid, had stated that nothing was known 

 of their breeding season but that ripe sexual products could be 

 had at irregular intervals during June, July and August. Col- 

 lecting therefore during 1902 and 1903 was entirely at random. 

 Incidentally the opportunity came to observe something about 

 their egg-laying habits. During 1907 and 1908 I have used 

 eggs of the same species for the study of other problems and 

 have had a chance to further verify and extend the observations 

 previously made. I wish here to express my appreciation to the 

 directors of the Marine Biological Laboratory for their kindness 

 and encouragement in helping me to prosecute this work. 



The observations mentioned in this paper pertain to two ques- 

 tions in particular. I have always experienced considerable dif- 

 ficulty in obtaining, when wanted, mature sexual products of 

 Avipliitrite. The first question therefore deals with the time of 

 egg-laying, in the hope that future investigators on this species 

 may be saved some trouble and disappointment. The second 

 question is concerned with the manner of depositing eggs. The 

 eggs and sperm float free in the body cavity and these products 

 are usually in various stages of development. This is true even 

 at the time when worms deposit the mature products in a manner 

 apparently normal. How is it possible to retain the coelomic 

 corpuscles and the unripe eggs and deposit the ripe sexual 

 products ? In a number of instances I have observed the act of 



327 



