OX THE OCCURRENCE AND FOOD HABITS OF 



CTEXOPHORES IN NEW JERSEY INLAND 



COASTAL WATERS. 



THURLOW C. NELSON. 



(From the Zoological Laboratory of Rutgers University and the Department of Biology 

 of the New Jersey Experiment Station.) 



I. 



Studies of the plankton organisms of New Jersey inland coastal 

 waters (Fig. i) which have been in progress since March 1919 

 reveal interesting facts regarding the occurrence and habits of 

 the ctenophores Mnemiopsis leidyi Agassiz, Pleiirobrachia brunnea 

 Mayer, and Beroe ovata Chamisso and Eisenhardt. All three of 

 these forms have been found at times in abundance in New 

 Jersey, but again they may be rare or absent. They must, 

 therefore, be considered as transient visitors to these waters. 

 This paper is presented with the hope that the observations 

 herein recorded may aid in the ultimate solution of some of the 

 problems concerned with the distribution of these comparatively 

 little known animals. 



The common comb-jelly or sea walnut of the northeastern 

 coast of the United States, Mnemiopsis leidyi, was frequently 

 found by Mayer ('12), off Newport, R. I., in great rafts. It was 

 well known in the Woods Hole region until about 1910 when it 

 practically disappeared and has not since been reported there in 

 numbers. 1 Sumner, Osborn, and Cole ('13), p. 579, report this 

 species as varying from scarce to very abundant throughout the 

 Woods Hole region, where it has been recorded by various 

 observers for every month in the year. It was apparently most 

 abundant here in September and in December. These authors 

 note the irregular occurrence of this ctenophore in different years, 



1 Mr. George M. Gray, Curator of the Supply Department at Woods Hole, 

 informs me in a letter of January 28, 1924, that nearly every year one or two 

 specimens are taken in the winter or in spring. I have been infonnrcl that numerous 

 Mnemiopsis were found here in September 1924 following an extcmlnl period of 

 easterly winds. 



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