BIGELOW: COAST WATER EXPLORATION OF 1913. 



321 



Although Pleurobrachia was widely distributed, it was by no means 

 uniformly abundant. Its chief centre was from off New York (Sta- 

 tions 10067, 10068) nearly to Cape May (Stations 10069, 10080), where 

 the deep water layers were filled with it, almost to the exclusion of 

 other plankton (p. 269), extending for some twenty-five or thirty miles 



Fig. 80.— Distribution of ctenophores, July-August, 1913. 



B, Beroeforskalii; 6, B. cucumis; m, Mnemiopsis leidji; p, Pleurobrachia 



pileus; P, P. pileus swarms , probable limit to P. swarms. 



, probable limit to Mnemiopsis in July. 



seaward (Stations 10072, 10070) beyond which their numbers rapidly 

 decreased. It was still numerous when this region was passed again on 

 August 1, on our way north (Station 10082). South of Cape May it 

 was much less common, and very few were taken over the shelf east 



