BREEDING HABITS OF IIETERONEREIS. 159 



Some other annelids (e. g., Amphitrite; see Scott, 1909) exhibit 

 a lunar periodicity in breeding habits. The periodicity in Nereis 

 limbata thus belongs to a large class of phenomena, which includes 

 breeding seasons of some plants as well as many other animals, 

 for which no adequate general cause has yet been found. 



III. THE LIFE HISTORY OF Nereis limbata. 

 This subject is still under investigation. It is obvious that 

 interpretation of the swarming behavior must wait for fairly 

 complete knowledge of the life history. The present indications 

 are that the worms either do not mature in the atokous condition, 

 or, if they do so, that it is at an earlier time of year than our collec- 

 tions were made. The atokous forms were secured both in 

 scrapings from piles of wharves and also by digging, and were 

 kept under observation in the laboratory. All that matured 

 underwent metamorphosis to the epitokous condition. Despite 

 repeated efforts we failed to rear mature worms from artificially 

 fertilized eggs. However, a few were raised to young worms 

 about 5 mm. in length, about eight weeks after fertilization; but 

 all of them died after an attempted change in culture methods. 



LITERATURE REFERRED TO. 

 Friedlander, Benedict. 



'98 Ueber den sogenannten Palolowurm. Biol. C'bl., Vol. XVIII. 

 Galloway, T. W., and Welch, Paul S. 



'li Studies on a Phosphorescent Bermudan Annelid, Odontosyllis enopla 



Verrill. Trans. Am. Entomological Soc., Vol. XXX. 

 Hempelmann, Fr. 



'n Zur Naturgeschichte von Nereis Dumerilii Aud. et Edw. Zoologica, Bd. 



25, Lief, i (Heft 62). 

 Izuka, Akira. 



'03 Observations on the Japanese Palolo. Journ. Coll. Imp. Univ., Tokyo, 



Vol. XVII., Art. II. 

 Mayer, A. G. 



'02 The Atlantic Palolo. Science Bulletin, Mus. Brooklyn Acad. Arts and 



ScL, Vol i. 



'03 An Atlantic Palolo, Staurocephalus gregarious. 

 '07 The Annual Swarming of the Atlantic Palolo. Seventh Internal. Zool. 



Congress. 



'08 Publication 102 Carnegie Inst., Washington. 

 Scott, John W. 



'09 Some Egg-laying Habits of A mphitriteornata Verrill. Biol. Bull., Vol. XVII. 



