METHODS OF PLANKTON RESEARCH. 535 



90 cm. in diameter. About one metre from the 

 month the net is attached to a second wooden ring, 

 to one point of which is attached an additional 

 rope from the ship, so that when the haul has been made 

 the net may be rapidly pulled up edgewise without 

 offering opposition to the water. The apex of the net 

 where the usual bucket is attached has a diameter of 

 10 centimetres. 



A modification of the " Brut " net, called the 

 " Scherbrutnetz," has been constructed to allow of the 

 application of such a net as the former to the collection 

 of the plankton from deeper layers. The essential feature 

 is a strong galvanised iron plate, hinged, as seen in fig. 5, 



Fig. 5. — The "Scherbrutnetz." 



to one side of the square mouth of the net. This " shear " 

 board is, however, not allowed to move freely, but is fixed 

 so that it makes an angle of 125° with the plane of the 

 mouth of the net. 



When this net is hauled the water presses against 



