THE HABITS AND EARLY DEVELOPMENT OF LINERGES MERCURIUS. 



By Edwin G. Conklin. 



During a part of April and May, 1905, while a guest of the Carnegie 

 Institution of Washington at its Marine Laboratory at Tortugas, Florida, 

 I had opportunity to study the habits and early development of the scypho- 

 medusan Lincrgcs mcrcurius Haeckel, but was unable at that time to complete 

 the work, owing to the sudden disappearance of these jelly-fishes. I spent 

 the month of July of the same year at the Bermuda Biological Station, but 

 did not find a single specimen of these medusje until the day on which I 

 saited for home, when they appeared in great numbers, but too late for me 

 to continue my work upon them. During the month of April, 1907, I was 

 again the guest of the Carnegie Institution at its temporary station at Nassau, 

 New Providence, Bahamas, and there obtained enough of these jelly-fishes 

 to continue the work which had been begun two years before. But here also 

 the work was interrupted by the sudden disappearance of these animals ; 

 however, I have decided to publish this report of my work, although it is 

 still in many respects incomplete, since I may not again in the near future 

 have an opportunity to studv these forms. 



HABITS. 



Occurrence.- The sudden appearance, in great numbers, of Linerges and 

 its equally sudden disappearance has been noted by other observers. The 

 animals began to appear when I first arrived in Tortugas, April 24, and in- 

 creased in numbers until April 28, on which day they were present in count- 

 less myriads, usually stretching in great windrows across the surface of the 

 water. On April 29 very few could be found ; on April 30 an extended search 

 all around the fort and harbor failed to reveal more than 20 individuals ; on 

 subsequent days none were present. They appeared and disappeared in a 

 similarly sudden manner at Nassau, between April 23 and April 30, and at 

 Bermuda between July 27 and August i. 



How is this sudden appearance of the Linerges swarm to be explained? 

 There is no evidence that they drift in on ocean currents from some other 

 locality and disappear in the manner in which they came. On the contrary, 

 they frequently occur in relatively inclosed areas, where currents are not 

 strong, and before or after the swarming they are not to be found in the 



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