38 



NATURALISl-S ASSISTANT. 



which affect such places. Sometimes, instead of having a 

 "beam," the trawl has two "wings" made of wood and 

 loaded on one edge so that they maintain an upright position. 

 These wings are attached to the rope after the fashion of a 

 kite so that the passage through the water forces them widely 

 apart. In this form, the upper edge of the net should be 

 floated with cork. 



The tangle, fig. 15, is another piece of appa.ratus for 



Fig. 14- 



marine collecting and is useful for obtaining such bottom 

 forms as are covered with spines. It consists of an iron bar, 

 having on each end a wheel. To the bar are attached about, 

 half a dozen chains, each chain having every few inches 

 bunches of hemp or untwisted rope. Such animals as the 

 Starfish, Brittle-stars and Shrimps, become entangled in the 

 bunches and are thus brought to the surface. 



Another method of obtaining forms from the bottom is by 

 pumping. This was first employed by Meyer and Mobius in 



