PLANKTON OF THE GULF OF MAINE 



257 



rate of 16,500 per square meter (an unusually rich catch for it in the gulf), but a sec- 

 ond vertical haul with the same net, hauled up at the same rate of speed and from a 



Fig. 78. — Localities where the vertical hauls have yielded a larger number of Metridia lucens per square meter than the 

 average for the respective month. 0, June to October; X. February to May. The hatched curve incloses the area 

 where it has been found notably abundant only in late winter and spring; the stippled curve where it has been found 

 abundant only in summer and autumn 



slightly greater depth (55 meters) at 10 p. m., gave a frequency of only 252 per 

 square meter. Evidently the shoal encountered by the first haul had drifted past 

 with the tide during the 7-hour interval before the second haul was made. Never- 



