PLANKTON OF THE GULF OF MAINE 



65 



so much deeper that it is prevented from entering Massachusetts Bay by the contour 

 of the bottom, and, in fact, hardly encroaches at all on the shallow coastal belt 

 within the 100-meter contour. Furthermore, the two agree in their scarcity in the 



Fig. 33.— Chief routes followed by planktonic immigrants entering the Gulf of Maine at different levels. \\\, immigrants 

 at the surface; 111, immigrants at intermediate levels; =, immigrants at the deepest level 



southwestern part of the basin of the gulf— that is, just where the physical data, to be 

 discussed elsewhere, locate the "dead water" in the anticlockwise eddy that occupies 

 the gulf. However, S. maxima, living in the deepest waters of the basin, must follow 



