The Development of Scyphomedusse. 221 



oar could not be thrust without hitting many at one blow. That 

 they were actually spawning was ascertained by raising specimens 

 from the water, when sperm was seen streaming freely from the 

 appendages of the lower surface, and eggs flowing along the channel 

 of their arms. It was about sunset and the closing night prevented 

 me from ascertaining how long they remained together. The next 

 day they were scattered by the wind, and a few days afterward im- 

 mense numbers were found stranded upon the rocks and long sand- 

 beach at Nahant." (1862, p. 76). A. Agassiz has also given express- 

 ion to similar views on this point, though without definite facts 

 other than the mere observation of the congregating of medusse 

 at periodic times. (1865, p. 46). 



Much more explicit is a recent reference of Conklin (1908, pp. 

 155-156), to the spawning of Linerges mercurius. In the case of 

 this medusa there seems little doubt as to the facts given by Conk- 

 lin and their bearing upon the matter under consideration. Some- 

 thing of a similar character is also known among Hydromedusae. 

 The senior author has, in connection with the account of the 

 development of Pennaria, made clear the intimate correlation of 

 the spawning habits. He has also referred to the interesting 

 occurrence of swarms of Rhegmatodes at certain times. But the 

 latter have not apparently been associated directly with the breed- 

 ing instinct, since they included specimens of all ages and con- 

 ditions of maturity. He has also expressed serious doubt (1904, 

 p. 26), of this interpretation as applicable to all cases. That the 

 view of Agassiz cited above may find an occasional warrant need 

 not be denied; but that it is general, or at slW frequent we do not 

 believe. In many years of observation little evidence has been 

 found to sustain the view. Furthermore, the fact that isolated 

 specimens of both Aurelia and Cyanea have been taken, males 

 and females bearing ripe gonads, the latter in various stages of 

 maturity and with eggs in various stages of development, would 

 further support it. Indeed, in the case of Cyanea, it is rather rare 

 to find any considerable numbers together. The first collection 

 included but three or four specimens, including both sexes. Again 

 in the case of Aurelia, which we collected in large numbers about 

 the first of August, there was no massing of numbers at any time. 



